diff --git a/src/main/ipc/profiles/orca-profile-org-members-handlers.ts b/src/main/ipc/profiles/orca-profile-org-members-handlers.ts
index 66dab1748ce..29e6a8ef904 100644
--- a/src/main/ipc/profiles/orca-profile-org-members-handlers.ts
+++ b/src/main/ipc/profiles/orca-profile-org-members-handlers.ts
@@ -1,4 +1,4 @@
-import { ORCA_ORG_NAME_MAX_LENGTH } from '../../../shared/orca-org-management'
+import { isValidOrgName, ORCA_ORG_NAME_MAX_LENGTH } from '../../../shared/orca-org-management'
 import type { OrcaProfileOrgCreateResult } from '../../../shared/orca-org-management'
 import { ipcMain } from 'electron'
 import type {
@@ -85,7 +85,7 @@ function orgMemberRemoveArgsFromUnknown(args: unknown): OrcaProfileOrgMemberRemo
 function orgCreateNameFromUnknown(args: unknown): string {
   const record = args && typeof args === 'object' ? (args as Record<string, unknown>) : {}
   const name = typeof record.name === 'string' ? record.name.trim() : ''
-  if (!name || name.length > ORCA_ORG_NAME_MAX_LENGTH) {
+  if (!name || name.length > ORCA_ORG_NAME_MAX_LENGTH || !isValidOrgName(name)) {
     throw new Error('invalid_orca_org_name')
   }
   return name
diff --git a/src/main/orca-profiles/profile-cloud-dev-org-members.ts b/src/main/orca-profiles/profile-cloud-dev-org-members.ts
index e5a72444869..877032a6f53 100644
--- a/src/main/orca-profiles/profile-cloud-dev-org-members.ts
+++ b/src/main/orca-profiles/profile-cloud-dev-org-members.ts
@@ -1,3 +1,4 @@
+import { isValidOrgName } from '../../shared/orca-org-management'
 import type { OrcaProfileOrgCreateResult } from '../../shared/orca-org-management'
 import { randomUUID } from 'node:crypto'
 import { addDevOrganization, removeDevOrganization } from './profile-cloud-dev-auth'
@@ -160,7 +161,7 @@ export function removeDevOrcaCloudOrgMember(
 
 export function createDevOrcaCloudOrg(name: string): OrcaProfileOrgCreateResult {
   const trimmed = name.trim()
-  if (!trimmed) {
+  if (!isValidOrgName(trimmed)) {
     return { status: 'invalid' }
   }
   const orgId = `dev-team-${randomUUID().slice(0, 8)}`
diff --git a/src/main/orca-profiles/profile-cloud-org-members-service.ts b/src/main/orca-profiles/profile-cloud-org-members-service.ts
index c06408e93a1..34769527669 100644
--- a/src/main/orca-profiles/profile-cloud-org-members-service.ts
+++ b/src/main/orca-profiles/profile-cloud-org-members-service.ts
@@ -285,6 +285,9 @@ export async function createOrcaProfileOrg(
       if (result.error.statusCode === 429) {
         return { status: 'rate-limited' }
       }
+      if (result.error.statusCode === 409) {
+        return { status: 'name-taken' }
+      }
       return result.error.statusCode === 400
         ? { status: 'invalid' }
         : { status: 'failed', error: result.error.message }
diff --git a/src/renderer/src/components/billing/team/TeamCreateView.tsx b/src/renderer/src/components/billing/team/TeamCreateView.tsx
index da54718870e..f90867ee730 100644
--- a/src/renderer/src/components/billing/team/TeamCreateView.tsx
+++ b/src/renderer/src/components/billing/team/TeamCreateView.tsx
@@ -1,4 +1,4 @@
-import { ORCA_ORG_NAME_MAX_LENGTH } from '../../../../../shared/orca-org-management'
+import { isValidOrgName, ORCA_ORG_NAME_MAX_LENGTH } from '../../../../../shared/orca-org-management'
 import { useId, useState } from 'react'
 import { ArrowRight, Users } from 'lucide-react'
 import { Button } from '@/components/ui/button'
@@ -27,6 +27,8 @@ export function TeamCreateView(props: TeamCreateViewProps): React.JSX.Element {
   const id = useId()
   const [name, setName] = useState('')
   const trimmed = name.trim()
+  const nameValid = isValidOrgName(trimmed)
+  const showRule = trimmed.length > 0 && !nameValid
   return (
     <div className="space-y-6">
       <section
@@ -53,7 +55,7 @@ export function TeamCreateView(props: TeamCreateViewProps): React.JSX.Element {
           className="mt-4 space-y-2"
           onSubmit={(event) => {
             event.preventDefault()
-            if (trimmed && !props.creating && !props.unavailable) {
+            if (nameValid && !props.creating && !props.unavailable) {
               props.onCreate(trimmed)
             }
           }}
@@ -70,8 +72,8 @@ export function TeamCreateView(props: TeamCreateViewProps): React.JSX.Element {
                 'auto.components.billing.team.teamNamePlaceholder',
                 'Acme Engineering'
               )}
-              aria-invalid={props.error ? true : undefined}
-              aria-describedby={props.error ? `${id}-error` : undefined}
+              aria-invalid={props.error || showRule ? true : undefined}
+              aria-describedby={props.error ? `${id}-error` : showRule ? `${id}-rule` : undefined}
               onChange={(event) => setName(event.target.value)}
               readOnly={props.creating}
               aria-disabled={props.creating || undefined}
@@ -79,7 +81,7 @@ export function TeamCreateView(props: TeamCreateViewProps): React.JSX.Element {
             />
             <Button
               type="submit"
-              disabled={!props.creating && (!trimmed || props.unavailable)}
+              disabled={!props.creating && (!nameValid || props.unavailable)}
               aria-disabled={props.creating || undefined}
             >
               {props.creating ? <LoadingSpinner className="size-3.5" /> : null}
@@ -97,6 +99,14 @@ export function TeamCreateView(props: TeamCreateViewProps): React.JSX.Element {
               )}
             </p>
           ) : null}
+          {showRule && !props.error ? (
+            <p id={`${id}-rule`} className="text-xs text-muted-foreground">
+              {t(
+                'auto.components.billing.team.createInvalid2',
+                'Use letters, numbers, spaces or underscores (up to 64).'
+              )}
+            </p>
+          ) : null}
           {props.error ? (
             <p id={`${id}-error`} role="alert" className="text-xs text-destructive">
               {props.error}
diff --git a/src/renderer/src/components/billing/team/team-copy.ts b/src/renderer/src/components/billing/team/team-copy.ts
index 267744223bd..1f42fde79f9 100644
--- a/src/renderer/src/components/billing/team/team-copy.ts
+++ b/src/renderer/src/components/billing/team/team-copy.ts
@@ -151,7 +151,12 @@ export function createTeamFailureCopy(
     case 'created':
       return null
     case 'invalid':
-      return t('auto.components.billing.team.createInvalid', 'Choose a different team name.')
+      return t(
+        'auto.components.billing.team.createInvalid2',
+        'Use letters, numbers, spaces or underscores (up to 64).'
+      )
+    case 'name-taken':
+      return t('auto.components.billing.team.nameTaken', 'That team name is taken. Try another.')
     case 'unsupported':
       return t(
         'auto.components.billing.team.createUnavailable',
diff --git a/src/renderer/src/i18n/locales/en.json b/src/renderer/src/i18n/locales/en.json
index c03b6738fa3..14a41a6099d 100644
--- a/src/renderer/src/i18n/locales/en.json
+++ b/src/renderer/src/i18n/locales/en.json
@@ -20313,7 +20313,6 @@
           "createdToast": "{{value0}} created",
           "createFailed": "Could not create the team. Try again.",
           "createHint": "Share one Orca Cloud plan with your teammates.",
-          "createInvalid": "Choose a different team name.",
           "createTitle": "Create a team",
           "createUnavailable": "Team creation isn’t available yet. Ask a teammate to invite you.",
           "createWorkspace": "Create a cloud workspace",
@@ -20413,7 +20412,9 @@
           "nowAdmin": "{{value0}} is now an admin",
           "nowMember": "{{value0}} is now a member",
           "nowOwner": "{{value0}} is now an owner",
-          "perSeatPerMonth": "{{value0}} per seat per month"
+          "perSeatPerMonth": "{{value0}} per seat per month",
+          "createInvalid2": "Use letters, numbers, spaces or underscores (up to 64).",
+          "nameTaken": "That team name is taken. Try another."
         },
         "manageBilling": "Manage billing",
         "comparePlans": "Compare plans",
diff --git a/src/shared/orca-org-management.test.ts b/src/shared/orca-org-management.test.ts
new file mode 100644
index 00000000000..3185b2258a0
--- /dev/null
+++ b/src/shared/orca-org-management.test.ts
@@ -0,0 +1,15 @@
+import { describe, expect, it } from 'vitest'
+import { isValidOrgName } from './orca-org-management'
+
+describe('isValidOrgName', () => {
+  it('accepts the sign-in provider character set up to 64 characters', () => {
+    expect(isValidOrgName('Acme Engineering')).toBe(true)
+    expect(isValidOrgName('team_42')).toBe(true)
+    expect(isValidOrgName('a'.repeat(64))).toBe(true)
+  })
+  it('rejects punctuation, empty names and names over 64 characters', () => {
+    expect(isValidOrgName('Acme, Inc.')).toBe(false)
+    expect(isValidOrgName('   ')).toBe(false)
+    expect(isValidOrgName('a'.repeat(65))).toBe(false)
+  })
+})
diff --git a/src/shared/orca-org-management.ts b/src/shared/orca-org-management.ts
index ce4c7314536..84e75e0f8af 100644
--- a/src/shared/orca-org-management.ts
+++ b/src/shared/orca-org-management.ts
@@ -9,12 +9,20 @@ export type OrcaProfileOrgCreateArgs = {
 }
 
 export const ORCA_ORG_NAME_MAX_LENGTH = 64
+/** The sign-in provider's rule for team names: letters, digits, spaces and underscores. */
+export const ORCA_ORG_NAME_PATTERN = /^[A-Za-z0-9_ ]{1,64}$/
+
+export function isValidOrgName(name: string): boolean {
+  return ORCA_ORG_NAME_PATTERN.test(name.trim())
+}
 
 /** 'unsupported': this Orca Cloud auth deployment has no route for the action yet. */
 export type OrcaProfileOrgCreateResult =
   | { status: 'created'; orgId: string; name: string }
   | { status: 'unconfigured' | 'reconnect-required' | 'unsupported' | 'rate-limited' }
   | { status: 'invalid' }
+  /** Another team already uses this name. */
+  | { status: 'name-taken' }
   | { status: 'failed'; error: string }
 
 export type OrcaOrgInviteConflictReason = 'already_member' | 'already_invited'