diff --git a/src/components/calendar/EventDetailSheet.tsx b/src/components/calendar/EventDetailSheet.tsx
index 959fc9d0..02365934 100644
--- a/src/components/calendar/EventDetailSheet.tsx
+++ b/src/components/calendar/EventDetailSheet.tsx
@@ -49,6 +49,7 @@ import {
   isOrganizer,
 } from '../../lib/calendar-participants';
 import { getEventEditability } from '../../lib/calendar-editability';
+import { useContactNameResolver } from '../../lib/contact-name-resolver';
 import { useCalendarLocale } from '../../lib/calendar-locale';
 import { useSheetDrag } from '../../lib/use-sheet-drag';
 
@@ -143,6 +144,9 @@ export function EventDetailSheet({
   const { locale, t } = useCalendarLocale();
   const [rsvpBusy, setRsvpBusy] = React.useState(false);
   const styles = React.useMemo(() => makeStyles(c), [c]);
+  // Bare addresses (the organizer above all — Stalwart drops its display
+  // name) render with the contact card's name instead of the raw email.
+  const resolveContactName = useContactNameResolver();
   const slideY = React.useRef(new Animated.Value(Dimensions.get('window').height)).current;
   const overlayOpacity = React.useRef(new Animated.Value(0)).current;
   const visible = !!event;
@@ -192,7 +196,7 @@ export function EventDetailSheet({
   const range = formatRange(event, timeFormat, locale);
   const recurrence = recurrenceLabel(event, t, locale);
   const reminders = alertsToReminders(event.alerts);
-  const participants = getParticipantList(event);
+  const participants = getParticipantList(event, { resolveName: resolveContactName });
   const location = event.locations ? Object.values(event.locations)[0]?.name : undefined;
   const videoUri = event.virtualLocations ? Object.values(event.virtualLocations)[0]?.uri : undefined;
   const isCancelled = event.status === 'cancelled';
@@ -365,9 +369,9 @@ export function EventDetailSheet({
                         </Text>
                       ) : null}
                     </Text>
-                    <Text style={styles.participantStatus}>
-                      {p.isOrganizer ? '' : statusLabel(p.status, t)}
-                    </Text>
+                    {/* The organizer is marked by the suffix; this shows their status
+                        (organizers default to accepted), like the dot. */}
+                    <Text style={styles.participantStatus}>{statusLabel(p.status, t)}</Text>
                   </View>
                 ))}
               </View>
diff --git a/src/components/calendar/EventModal.tsx b/src/components/calendar/EventModal.tsx
index 07b5f496..35d2b7bd 100644
--- a/src/components/calendar/EventModal.tsx
+++ b/src/components/calendar/EventModal.tsx
@@ -68,6 +68,7 @@ import {
 } from '../../lib/calendar-participants';
 import { Button } from '..';
 import { ParticipantInput } from './ParticipantInput';
+import { useContactNameResolver } from '../../lib/contact-name-resolver';
 import { RecurrenceEditor } from './RecurrenceEditor';
 
 type RecurrenceOption = 'none' | 'daily' | 'weekly' | 'monthly' | 'yearly' | 'custom';
@@ -187,6 +188,7 @@ export function EventModal({
   const timeFormat = useSettingsStore((s) => s.calendarTimeFormat);
   const timeLabelPattern = timePattern(timeFormat);
   const isEdit = !!event;
+  const resolveContactName = useContactNameResolver();
 
   const [title, setTitle] = React.useState('');
   const [description, setDescription] = React.useState('');
@@ -352,8 +354,12 @@ export function EventModal({
       };
       const organizerEmail = currentUserEmails[0];
       if (attendees.length > 0 && organizerEmail) {
+        // A new event has no participants yet, so it would store an empty
+        // organizer name; fall back to the contact card / account name.
         const organizerName =
-          (event ? getParticipantList(event).find((p) => p.isOrganizer)?.name : '') || '';
+          (event ? getParticipantList(event).find((p) => p.isOrganizer)?.name : '')
+          || resolveContactName(organizerEmail)
+          || '';
         data.participants = buildParticipantMap(
           { name: organizerName, email: organizerEmail },
           attendees,
diff --git a/src/lib/__tests__/calendar-participants.test.ts b/src/lib/__tests__/calendar-participants.test.ts
index 03157401..a5819ec1 100644
--- a/src/lib/__tests__/calendar-participants.test.ts
+++ b/src/lib/__tests__/calendar-participants.test.ts
@@ -3,6 +3,7 @@ import type { CalendarEvent } from '../../api/types';
 import {
   buildParticipantMap,
   collectUserCalendarAddresses,
+  getParticipantCount,
   getParticipantList,
   getStatusCounts,
   getUserParticipantId,
@@ -89,3 +90,84 @@ describe('seedAttendees', () => {
     expect(emails).toHaveLength(3);
   });
 });
+
+describe('getParticipantList dedupe, names and organizer status', () => {
+  const org = { name: 'Alice', email: 'alice@example.com', roles: { owner: true }, participationStatus: 'accepted' as const };
+  const bob = { name: 'Bob', email: 'bob@example.com', roles: { attendee: true }, participationStatus: 'needs-action' as const };
+
+  it('renders the organizer once when the server also emits them as an attendee', () => {
+    const list = getParticipantList({
+      organizerCalendarAddress: 'mailto:alice@example.com',
+      participants: {
+        org: { ...org, name: '' },
+        att1: bob,
+        att2: { ...bob, name: 'Carol', email: 'carol@example.com' },
+        orgDup: { ...bob, name: '', email: 'alice@example.com' },
+      },
+    });
+    expect(list).toHaveLength(3);
+    const alices = list.filter((p) => p.email === 'alice@example.com');
+    expect(alices).toHaveLength(1);
+    expect(alices[0]).toMatchObject({ isOrganizer: true, status: 'accepted' });
+  });
+
+  it('keeps the real RSVP when the first entry of an address never replied', () => {
+    const list = getParticipantList({
+      organizerCalendarAddress: 'mailto:alice@example.com',
+      participants: {
+        att1: { ...bob, name: '', email: 'alice@example.com' },
+        org,
+      },
+    });
+    expect(list).toHaveLength(1);
+    expect(list[0]).toMatchObject({ isOrganizer: true, status: 'accepted', name: 'Alice' });
+  });
+
+  it('merges duplicate attendees case-insensitively, first-seen name wins', () => {
+    const list = getParticipantList({
+      participants: {
+        att1: bob,
+        att2: { ...bob, name: 'Bobby', email: 'BOB@example.com', participationStatus: 'accepted' },
+      },
+    });
+    expect(list).toHaveLength(1);
+    expect(list[0]).toMatchObject({ name: 'Bob', status: 'accepted' });
+  });
+
+  it('shows a statusless organizer as accepted, not pending', () => {
+    const list = getParticipantList(event);
+    expect(list.find((p) => p.isOrganizer)?.status).toBe('accepted');
+  });
+
+  it('fills missing names from resolveName without overriding event data', () => {
+    const resolveName = (email: string) => (email.startsWith('alice') || email.startsWith('bob') ? 'Contact' : undefined);
+    const list = getParticipantList(
+      { participants: { org: { ...org, name: '' }, att1: bob } },
+      { resolveName },
+    );
+    expect(list.find((p) => p.email === 'alice@example.com')?.name).toBe('Contact');
+    expect(list.find((p) => p.email === 'bob@example.com')?.name).toBe('Bob');
+  });
+
+  it('keeps entries without an address unmerged', () => {
+    const list = getParticipantList({
+      participants: {
+        org,
+        ghost1: { name: 'No Address', participationStatus: 'needs-action' },
+        ghost2: { name: 'Also No Address', participationStatus: 'accepted' },
+      },
+    });
+    expect(list).toHaveLength(3);
+  });
+
+  it('counts addresses, not raw entries', () => {
+    expect(getParticipantCount({
+      participants: {
+        org: { ...org, name: '' },
+        att1: bob,
+        orgDup: { ...bob, name: '', email: 'alice@example.com' },
+        ghost: { name: 'No Address' },
+      },
+    })).toBe(3);
+  });
+});
diff --git a/src/lib/__tests__/contact-name-resolver.test.ts b/src/lib/__tests__/contact-name-resolver.test.ts
new file mode 100644
index 00000000..2515b58a
--- /dev/null
+++ b/src/lib/__tests__/contact-name-resolver.test.ts
@@ -0,0 +1,109 @@
+import { describe, it, expect } from 'vitest';
+import type { ContactCard } from '../../api/types';
+import { buildContactNameResolver } from '../contact-name-resolver';
+
+// A bare address in the event data must display the contact card's name,
+// while names the event already carries stay authoritative — the resolver
+// only ever fills (webmail #738).
+
+function makeContact(emails: string[], name?: string, overrides: Partial<ContactCard> = {}): ContactCard {
+  return {
+    id: Math.random().toString(36).slice(2),
+    addressBookIds: { ab1: true },
+    emails: Object.fromEntries(emails.map((address, i) => [`${i}`, { address }])),
+    ...(name ? { name: { full: name } } : {}),
+    ...overrides,
+  } as ContactCard;
+}
+
+describe('buildContactNameResolver', () => {
+  it('maps every address of a contact to its display name, case-insensitively', () => {
+    const resolver = buildContactNameResolver([
+      makeContact(['alice@example.com', 'alice.smith@example.com'], 'Alice'),
+    ]);
+    expect(resolver('alice@example.com')).toBe('Alice');
+    expect(resolver('  ALICE.SMITH@EXAMPLE.COM ')).toBe('Alice');
+  });
+
+  it('keeps the first contact when several hold the same address', () => {
+    const resolver = buildContactNameResolver([
+      makeContact(['bob@example.com'], 'First Bob'),
+      makeContact(['bob@example.com'], 'Second Bob'),
+    ]);
+    expect(resolver('bob@example.com')).toBe('First Bob');
+  });
+
+  it('skips cards whose only name is an address, and unknown or blank addresses', () => {
+    const resolver = buildContactNameResolver([makeContact(['noname@example.com'])]);
+    expect(resolver('noname@example.com')).toBeUndefined();
+    expect(resolver('unknown@example.com')).toBeUndefined();
+    expect(resolver('   ')).toBeUndefined();
+  });
+
+  it('falls back to a card with the same local part on a related domain', () => {
+    const resolver = buildContactNameResolver([
+      makeContact(['zhang@example.com'], 'Zhang'),
+      makeContact(['carol@node-example.com'], 'Carol'),
+    ]);
+    expect(resolver('zhang@node-example.com')).toBe('Zhang');
+    expect(resolver('zhang@mail.example.com')).toBe('Zhang');
+    expect(resolver('carol@example.com')).toBe('Carol');
+  });
+
+  it('does not fall back across unrelated or merely string-suffixed domains', () => {
+    const resolver = buildContactNameResolver([makeContact(['dave@example.com'], 'Dave')]);
+    expect(resolver('dave@gmail.com')).toBeUndefined();
+    expect(resolver('dave@xexample.com')).toBeUndefined();
+  });
+
+  it('returns nothing when related-domain cards disagree on the name', () => {
+    const disagree = buildContactNameResolver([
+      makeContact(['eve@example.com'], 'Eve One'),
+      makeContact(['eve@mail.example.com'], 'Eve Two'),
+    ]);
+    expect(disagree('eve@x.mail.example.com')).toBeUndefined();
+    const agree = buildContactNameResolver([
+      makeContact(['eve@example.com'], 'Eve'),
+      makeContact(['eve@mail.example.com'], 'Eve'),
+    ]);
+    expect(agree('eve@x.mail.example.com')).toBe('Eve');
+  });
+
+  it('uses the account name, then the identity name, for the user\'s own addresses', () => {
+    const resolver = buildContactNameResolver(
+      [],
+      [{ name: 'Old Name', email: 'zhang@node-example.com' }, { name: 'Ident', email: 'z@other.example' }],
+      [
+        { name: 'New Name', email: 'zhang@node-example.com', username: 'zhang' },
+        { name: 'Login', email: undefined, username: 'login@example.com' },
+      ],
+    );
+    expect(resolver('zhang@node-example.com')).toBe('New Name');
+    expect(resolver('z@other.example')).toBe('Ident');
+    expect(resolver('login@example.com')).toBe('Login');
+    // A short username is not an address.
+    expect(resolver('zhang@elsewhere.example')).toBeUndefined();
+  });
+
+  it('skips account names that are just the address', () => {
+    const resolver = buildContactNameResolver([], [], [
+      { name: 'zhang@node-example.com', email: 'zhang@node-example.com' },
+    ]);
+    expect(resolver('zhang@node-example.com')).toBeUndefined();
+  });
+
+  it('ranks contact cards (exact, then related-domain) above account and identity names', () => {
+    const exact = buildContactNameResolver(
+      [makeContact(['zhang@node-example.com'], 'Card')],
+      [{ name: 'Identity', email: 'zhang@node-example.com' }],
+      [{ name: 'Account', email: 'zhang@node-example.com' }],
+    );
+    expect(exact('zhang@node-example.com')).toBe('Card');
+    const related = buildContactNameResolver(
+      [makeContact(['zhang@example.com'], 'Card remark')],
+      [],
+      [{ name: 'Account', email: 'zhang@node-example.com' }],
+    );
+    expect(related('zhang@node-example.com')).toBe('Card remark');
+  });
+});
diff --git a/src/lib/calendar-participants.ts b/src/lib/calendar-participants.ts
index 584a2152..ec7842ab 100644
--- a/src/lib/calendar-participants.ts
+++ b/src/lib/calendar-participants.ts
@@ -127,23 +127,83 @@ export function getUserStatus(
   return null;
 }
 
-export function getParticipantList(event: Partial<CalendarEvent>): ParticipantInfo[] {
+/** When the same address appears in two participant entries, a real RSVP on
+ *  either one beats a missing/"needs-action" one — the duplicate is always the
+ *  entry that never replied. Between two real replies the first-seen entry
+ *  wins; such conflicts do not occur in practice. */
+function betterStatus(
+  current: Participant['participationStatus'] | undefined,
+  incoming: Participant['participationStatus'] | undefined,
+): Participant['participationStatus'] {
+  if (current === 'needs-action' && incoming && incoming !== 'needs-action') return incoming;
+  return current || 'needs-action';
+}
+
+export interface ParticipantListOptions {
+  /**
+   * Fills `ParticipantInfo.name` for participants whose event data carries no
+   * name. Stalwart drops the ORGANIZER display name on its iCalendar
+   * round-trip, so the organizer (and attendees added by bare address) render
+   * as a bare email until the contact card's name is looked up.
+   */
+  resolveName?: (email: string) => string | undefined;
+}
+
+export function getParticipantList(
+  event: Partial<CalendarEvent>,
+  options?: ParticipantListOptions,
+): ParticipantInfo[] {
   if (!event.participants) return [];
   // Stalwart rebuilds the ORGANIZER line into a participant that carries only
   // `calendarAddress` — no `roles` at all — so `roles.owner` alone would treat
   // the organizer as a plain attendee on every re-read (#731).
   const organizerEmails = getEventOrganizerEmails(event);
-  return Object.entries(event.participants).map(([id, p]) => {
+  const resolveName = options?.resolveName;
+
+  // The same address can legitimately arrive twice: the organizer as both the
+  // ORGANIZER-derived participant and an ATTENDEE line (server-side
+  // scheduling, or events written before #731), or an attendee pasted twice.
+  // Render each address once by folding later entries into the first-seen
+  // one — otherwise every list and count shows a phantom participant.
+  const list: ParticipantInfo[] = [];
+  const byEmail = new Map<string, ParticipantInfo>();
+
+  for (const [id, p] of Object.entries(event.participants)) {
     const email = getParticipantEmail(p);
-    return {
+    const key = email.trim().toLowerCase();
+    const isOrganizer = !!p.roles?.owner || (!!key && organizerEmails.includes(key));
+
+    const existing = key ? byEmail.get(key) : undefined;
+    if (existing) {
+      if (!existing.name && p.name) existing.name = p.name;
+      if (isOrganizer) existing.isOrganizer = true;
+      existing.status = betterStatus(existing.status, p.participationStatus);
+      continue;
+    }
+
+    const entry: ParticipantInfo = {
       id,
       name: p.name || '',
       email,
       status: p.participationStatus || 'needs-action',
-      isOrganizer:
-        !!p.roles?.owner || (!!email && organizerEmails.includes(email.toLowerCase())),
+      isOrganizer,
     };
-  });
+    if (key) byEmail.set(key, entry);
+    list.push(entry);
+  }
+
+  for (const entry of list) {
+    if (!entry.name && entry.email && resolveName) {
+      entry.name = resolveName(entry.email) || '';
+    }
+    // The organizer owes no reply to their own invitation; a missing status
+    // must not read as "pending" next to the organizer marker. Matches
+    // getStatusCounts, which excludes the organizer from pending totals.
+    if (entry.isOrganizer && entry.status === 'needs-action') {
+      entry.status = 'accepted';
+    }
+  }
+  return list;
 }
 
 export function getStatusCounts(event: Partial<CalendarEvent>): StatusCounts {
@@ -163,7 +223,20 @@ export function getStatusCounts(event: Partial<CalendarEvent>): StatusCounts {
 
 export function getParticipantCount(event: Partial<CalendarEvent>): number {
   if (!event.participants) return 0;
-  return Object.keys(event.participants).length;
+  // Count addresses, not raw entries: an organizer the server emits twice must
+  // not inflate the count. Entries without any address cannot be merged, so
+  // they count individually.
+  const seen = new Set<string>();
+  let count = 0;
+  for (const p of Object.values(event.participants)) {
+    const key = getParticipantEmail(p).trim().toLowerCase();
+    if (key) {
+      if (seen.has(key)) continue;
+      seen.add(key);
+    }
+    count++;
+  }
+  return count;
 }
 
 export interface Attendee {
diff --git a/src/lib/contact-name-resolver.ts b/src/lib/contact-name-resolver.ts
new file mode 100644
index 00000000..be7c7c96
--- /dev/null
+++ b/src/lib/contact-name-resolver.ts
@@ -0,0 +1,158 @@
+import React from 'react';
+import type { ContactCard } from '../api/types';
+import { useAccountStore } from '../stores/account-store';
+import { useContactsStore } from '../stores/contacts-store';
+import { useSettingsStore } from '../stores/settings-store';
+import { getContactDisplayName } from './contact-utils';
+
+// Port of the webmail's hooks/use-contact-name-resolver.ts (8cbc5bc5,
+// 6f99c017): names for participants whose event data carries only a bare
+// address.
+
+/** Domains are related when one extends the other at a label boundary —
+ *  "node-example.com" vs "example.com" (host-prefixed) or "mail.example.com" vs
+ *  "example.com" (subdomain). Stalwart deployments commonly expose one account
+ *  under several such domains, so a participant address and the contact card
+ *  holding that person's name may differ in domain while naming the same
+ *  person. A pure string suffix ("xexample.com" vs "example.com") is NOT
+ *  related — the character at the split must be "." or "-". */
+function isRelatedDomain(a: string, b: string): boolean {
+  if (a === b) return true;
+  const longer = a.length >= b.length ? a : b;
+  const shorter = a.length >= b.length ? b : a;
+  if (!longer.endsWith(shorter)) return false;
+  const boundary = longer[longer.length - shorter.length - 1];
+  return boundary === '.' || boundary === '-';
+}
+
+interface IdentityLike {
+  name?: string;
+  email?: string;
+}
+
+interface AccountLike {
+  name?: string;
+  email?: string;
+  username?: string;
+}
+
+/**
+ * Build an email → display-name lookup. Resolution order (first hit wins):
+ *
+ *  1. Contact card holding the exact address — the user's curated data, so it
+ *     outranks everything else.
+ *  2. Contact card with the same local part on a related domain (the
+ *     alias-domain case above). Only applied when exactly one name matches;
+ *     two cards disagreeing means we cannot know which person it is.
+ *  3. The account's display name for the user's own addresses — the organizer
+ *     of a self-created event is the user, and Stalwart strips the participant
+ *     name on its iCalendar round-trip.
+ *  4. The identity From-name.
+ *
+ * Cards with no resolvable name contribute nothing, so whatever name the event
+ * itself carries always stays authoritative and this resolver is a pure
+ * fallback for bare addresses.
+ */
+export function buildContactNameResolver(
+  contacts: ReadonlyArray<ContactCard>,
+  identities: ReadonlyArray<IdentityLike> = [],
+  accounts: ReadonlyArray<AccountLike> = [],
+): (email: string) => string | undefined {
+  const contactNamesByEmail = new Map<string, string>();
+  const contactNamesByLocalPart = new Map<string, Array<{ domain: string; name: string }>>();
+  const accountNamesByEmail = new Map<string, string>();
+  const identityNamesByEmail = new Map<string, string>();
+
+  /** Register `name` for `address` unless it is just the address itself —
+   *  several name sources default to the email and would add nothing over the
+   *  bare address every renderer already shows. */
+  const register = (map: Map<string, string>, name: string | undefined, address: string | undefined) => {
+    const trimmedName = name?.trim();
+    const key = address?.trim().toLowerCase();
+    if (!trimmedName || !key || map.has(key)) return;
+    if (trimmedName.toLowerCase() === key) return;
+    map.set(key, trimmedName);
+  };
+
+  for (const contact of contacts) {
+    const name = getContactDisplayName(contact).trim();
+    if (!name || !contact.emails) continue;
+    // getContactDisplayName falls back to the first email address, so a card
+    // whose "name" is just one of its addresses is equally useless here.
+    const nameIsJustAnAddress = Object.values(contact.emails).some(
+      (e) => e.address?.trim().toLowerCase() === name.toLowerCase(),
+    );
+    if (nameIsJustAnAddress) continue;
+    for (const { address } of Object.values(contact.emails)) {
+      const key = address?.trim().toLowerCase();
+      if (!key || contactNamesByEmail.has(key)) continue;
+      contactNamesByEmail.set(key, name);
+      const [localPart, ...rest] = key.split('@');
+      const domain = rest.join('@');
+      if (localPart && domain) {
+        const bucket = contactNamesByLocalPart.get(localPart) ?? [];
+        bucket.push({ domain, name });
+        contactNamesByLocalPart.set(localPart, bucket);
+      }
+    }
+  }
+
+  for (const account of accounts) {
+    register(accountNamesByEmail, account.name, account.email);
+    // A short login username ("zhang") is not an address; only match
+    // usernames that actually carry a domain.
+    if (account.username?.includes('@')) {
+      register(accountNamesByEmail, account.name, account.username);
+    }
+  }
+
+  for (const identity of identities) {
+    register(identityNamesByEmail, identity.name, identity.email);
+  }
+
+  return (email: string) => {
+    const key = email?.trim().toLowerCase();
+    if (!key) return undefined;
+
+    // 1. Exact address on a contact card.
+    const exact = contactNamesByEmail.get(key);
+    if (exact) return exact;
+
+    // 2. Same local part on a related domain. Ambiguous matches resolve to
+    // nothing rather than to a guess.
+    const [localPart, ...rest] = key.split('@');
+    const domain = rest.join('@');
+    if (localPart && domain) {
+      const candidates = new Set<string>();
+      for (const candidate of contactNamesByLocalPart.get(localPart) ?? []) {
+        if (isRelatedDomain(candidate.domain, domain)) candidates.add(candidate.name);
+      }
+      if (candidates.size === 1) return candidates.values().next().value;
+    }
+
+    // 3. The user's own account display name, then 4. the identity From-name.
+    return accountNamesByEmail.get(key) ?? identityNamesByEmail.get(key);
+  };
+}
+
+/**
+ * Participant rows show a contact's display name when the event data itself
+ * carries only a bare address. Memoised on the contact, account and identity
+ * lists, so it recomputes only when one of them actually changes.
+ */
+export function useContactNameResolver(): (email: string) => string | undefined {
+  const contacts = useContactsStore((s) => s.contacts);
+  const identities = useSettingsStore((s) => s.identities);
+  const accounts = useAccountStore((s) => s.accounts);
+  return React.useMemo(
+    () =>
+      buildContactNameResolver(
+        contacts,
+        identities,
+        // AccountEntry calls the display name `displayName`; map it onto the
+        // generic `name` the resolver works with.
+        accounts.map((a) => ({ name: a.displayName, email: a.email, username: a.username })),
+      ),
+    [contacts, identities, accounts],
+  );
+}