diff --git a/src/main/gitlab/client-mr-review-actions.test.ts b/src/main/gitlab/client-mr-review-actions.test.ts
index 4d651bdc618..37c5b49fa5f 100644
--- a/src/main/gitlab/client-mr-review-actions.test.ts
+++ b/src/main/gitlab/client-mr-review-actions.test.ts
@@ -451,4 +451,69 @@ describe('gitlab client — MR operations', () => {
       )
     })
   })
+  // Why: only `api`/`auth` define --hostname, so the `mr` subcommands must take
+  // the self-hosted host through GITLAB_HOST or glab exits on an unknown flag.
+  describe('mr subcommands against a self-hosted SSH host', () => {
+    const projectRef = { host: 'gitlab.example.internal', path: 'g/p' }
+
+    it('merges without --hostname and passes the host through GITLAB_HOST', async () => {
+      glabExecFileAsyncMock.mockResolvedValueOnce({ stdout: '', stderr: '' })
+
+      await expect(mergeMR('/repo', 6, 'merge', undefined, 'conn-1', projectRef)).resolves.toEqual({
+        ok: true
+      })
+
+      const [args, options] = glabExecFileAsyncMock.mock.calls[0]
+      expect(args).toEqual(['mr', 'merge', '6', '-R', 'g/p', '--yes'])
+      expect(options.env?.GITLAB_HOST).toBe('gitlab.example.internal')
+    })
+
+    it('keeps the squash flag while routing the host through the environment', async () => {
+      glabExecFileAsyncMock.mockResolvedValueOnce({ stdout: '', stderr: '' })
+
+      await expect(mergeMR('/repo', 6, 'squash', undefined, 'conn-1', projectRef)).resolves.toEqual(
+        { ok: true }
+      )
+
+      const [args, options] = glabExecFileAsyncMock.mock.calls[0]
+      expect(args).toEqual(['mr', 'merge', '6', '-R', 'g/p', '--yes', '--squash'])
+      expect(options.env?.GITLAB_HOST).toBe('gitlab.example.internal')
+    })
+
+    it('closes without --hostname and passes the host through GITLAB_HOST', async () => {
+      glabExecFileAsyncMock.mockResolvedValueOnce({ stdout: '', stderr: '' })
+
+      await expect(closeMR('/repo', 6, undefined, 'conn-1', projectRef)).resolves.toEqual({
+        ok: true
+      })
+
+      const [args, options] = glabExecFileAsyncMock.mock.calls[0]
+      expect(args).toEqual(['mr', 'close', '6', '-R', 'g/p'])
+      expect(options.env?.GITLAB_HOST).toBe('gitlab.example.internal')
+    })
+
+    it('reopens without --hostname and passes the host through GITLAB_HOST', async () => {
+      glabExecFileAsyncMock.mockResolvedValueOnce({ stdout: '', stderr: '' })
+
+      await expect(reopenMR('/repo', 6, undefined, 'conn-1', projectRef)).resolves.toEqual({
+        ok: true
+      })
+
+      const [args, options] = glabExecFileAsyncMock.mock.calls[0]
+      expect(args).toEqual(['mr', 'reopen', '6', '-R', 'g/p'])
+      expect(options.env?.GITLAB_HOST).toBe('gitlab.example.internal')
+    })
+
+    it('leaves the environment untouched for a local workspace', async () => {
+      glabExecFileAsyncMock.mockResolvedValueOnce({ stdout: '', stderr: '' })
+
+      await expect(mergeMR('/repo', 6, 'merge', undefined, null, projectRef)).resolves.toEqual({
+        ok: true
+      })
+
+      const [args, options] = glabExecFileAsyncMock.mock.calls[0]
+      expect(args).toEqual(['mr', 'merge', '6', '-R', 'g/p', '--yes'])
+      expect(options.env).toBeUndefined()
+    })
+  })
 })
diff --git a/src/main/gitlab/gitlab-project-ref-resolution.ts b/src/main/gitlab/gitlab-project-ref-resolution.ts
index c337c01ae89..293030960e7 100644
--- a/src/main/gitlab/gitlab-project-ref-resolution.ts
+++ b/src/main/gitlab/gitlab-project-ref-resolution.ts
@@ -1,6 +1,7 @@
 import { glabExecFileAsync } from '../git/runner'
 import type { GitAdmissionTier } from '../git/command-runner/git-exec-options'
 import { shouldProbeGitRemote } from '../git/remote-name-listing'
+import { addWslEnvKeys } from '../wsl-env'
 import { isTransientGitProbeError, readRemoteUrl } from '../git/remote-url-probe'
 import { NEGATIVE_ENTRY_TTL_MS } from '../git/remote-ref-probe-cache'
 import { getSshGitProviderGeneration } from '../providers/ssh-git-dispatch'
@@ -275,6 +276,22 @@ export function glabHostnameArgs(
   return connectionId && projectRef?.host ? ['--hostname', projectRef.host] : []
 }
 
+/** Why: only `api`/`auth` define `--hostname`; `mr` and `issue` subcommands reject it (#12193). */
+export function glabHostEnvOptions(
+  projectRef: Pick<ProjectRef, 'host'> | null | undefined,
+  connectionId?: string | null
+): { env?: NodeJS.ProcessEnv } {
+  if (!connectionId || !projectRef?.host) {
+    return {}
+  }
+  const env: NodeJS.ProcessEnv = { ...process.env, GITLAB_HOST: projectRef.host }
+  if (process.platform === 'win32') {
+    // Why: spawn env stops at the wsl.exe boundary unless WSLENV names the var.
+    addWslEnvKeys(env, ['GITLAB_HOST'])
+  }
+  return { env }
+}
+
 async function isGlabConfiguredForRemoteHost(
   repoPath: string,
   projectRef: Pick<ProjectRef, 'host'>,
diff --git a/src/main/gitlab/gl-utils.test.ts b/src/main/gitlab/gl-utils.test.ts
index 2c8b36dd0ec..a895e4702e9 100644
--- a/src/main/gitlab/gl-utils.test.ts
+++ b/src/main/gitlab/gl-utils.test.ts
@@ -25,6 +25,7 @@ import {
   parseGlabJsonList,
   parseGlabPaginationHeader,
   isMissingJobLogError,
+  glabHostEnvOptions,
   getProjectRef,
   getProjectRefForRemote,
   parseGlabApiResponse,
@@ -698,3 +699,47 @@ describe('parseGlabPaginationHeader', () => {
     expect(parseGlabPaginationHeader('-3', 0)).toBeUndefined()
   })
 })
+
+describe('glabHostEnvOptions', () => {
+  const projectRef = { host: 'gitlab.example.internal' }
+
+  afterEach(() => {
+    vi.unstubAllGlobals()
+    vi.restoreAllMocks()
+  })
+
+  it('carries the host in GITLAB_HOST for a connection-backed workspace', () => {
+    const { env } = glabHostEnvOptions(projectRef, 'conn-1')
+
+    expect(env?.GITLAB_HOST).toBe('gitlab.example.internal')
+  })
+
+  it('returns nothing for a local workspace', () => {
+    expect(glabHostEnvOptions(projectRef, null)).toEqual({})
+    expect(glabHostEnvOptions(projectRef, undefined)).toEqual({})
+  })
+
+  it('returns nothing when the project ref carries no host', () => {
+    expect(glabHostEnvOptions(null, 'conn-1')).toEqual({})
+    expect(glabHostEnvOptions({ host: '' }, 'conn-1')).toEqual({})
+  })
+
+  // Why: spawn env stops at the wsl.exe boundary, so Windows has to name the
+  // variable in WSLENV or glab in the distro never sees the host.
+  it('forwards GITLAB_HOST through WSLENV on Windows', () => {
+    vi.spyOn(process, 'platform', 'get').mockReturnValue('win32')
+
+    const { env } = glabHostEnvOptions(projectRef, 'conn-1')
+
+    expect(env?.GITLAB_HOST).toBe('gitlab.example.internal')
+    expect(env?.WSLENV?.split(':')).toContain('GITLAB_HOST')
+  })
+
+  it('leaves WSLENV alone off Windows', () => {
+    vi.spyOn(process, 'platform', 'get').mockReturnValue('darwin')
+
+    const { env } = glabHostEnvOptions(projectRef, 'conn-1')
+
+    expect(env?.WSLENV).toBe(process.env.WSLENV)
+  })
+})
diff --git a/src/main/gitlab/gl-utils.ts b/src/main/gitlab/gl-utils.ts
index f31c47105de..0991ed520cd 100644
--- a/src/main/gitlab/gl-utils.ts
+++ b/src/main/gitlab/gl-utils.ts
@@ -18,6 +18,7 @@ export {
   getIssueProjectRef,
   getProjectRef,
   getProjectRefForRemote,
+  glabHostEnvOptions,
   glabHostnameArgs,
   glabRepoExecOptions,
   parseGlabAuthStatusHosts,
diff --git a/src/main/gitlab/issue-update.ts b/src/main/gitlab/issue-update.ts
index 369e889ff09..2181b6e8208 100644
--- a/src/main/gitlab/issue-update.ts
+++ b/src/main/gitlab/issue-update.ts
@@ -5,6 +5,7 @@ import {
   classifyGlabError,
   getGlabKnownHosts,
   glabExecFileAsync,
+  glabHostEnvOptions,
   glabHostnameArgs,
   glabRepoExecOptions,
   release,
@@ -56,17 +57,10 @@ export async function updateIssue(
     await acquire()
     try {
       const cmd = updates.state === 'closed' ? 'close' : 'reopen'
-      await glabExecFileAsync(
-        [
-          'issue',
-          cmd,
-          String(issueNumber),
-          '-R',
-          repoFlag,
-          ...glabHostnameArgs(projectRef, connectionId)
-        ],
-        glabRepoExecOptions(repoPath, connectionId, localGitOptions)
-      )
+      await glabExecFileAsync(['issue', cmd, String(issueNumber), '-R', repoFlag], {
+        ...glabRepoExecOptions(repoPath, connectionId, localGitOptions),
+        ...glabHostEnvOptions(projectRef, connectionId)
+      })
     } catch (err) {
       const stderr = err instanceof Error ? err.message : String(err)
       // Treat "already closed/reopened" as a no-op (matches gh path).
@@ -102,14 +96,7 @@ export async function updateIssue(
   }
 
   // Field edits via `glab issue update`.
-  const editArgs: string[] = [
-    'issue',
-    'update',
-    String(issueNumber),
-    '-R',
-    repoFlag,
-    ...glabHostnameArgs(projectRef, connectionId)
-  ]
+  const editArgs: string[] = ['issue', 'update', String(issueNumber), '-R', repoFlag]
   let hasEditArgs = false
 
   if (updates.title) {
@@ -136,10 +123,10 @@ export async function updateIssue(
   if (hasEditArgs) {
     await acquire()
     try {
-      await glabExecFileAsync(
-        editArgs,
-        glabRepoExecOptions(repoPath, connectionId, localGitOptions)
-      )
+      await glabExecFileAsync(editArgs, {
+        ...glabRepoExecOptions(repoPath, connectionId, localGitOptions),
+        ...glabHostEnvOptions(projectRef, connectionId)
+      })
     } catch (err) {
       const stderr = err instanceof Error ? err.message : String(err)
       errors.push(classifyGlabError(stderr).message)
diff --git a/src/main/gitlab/issues.test.ts b/src/main/gitlab/issues.test.ts
index 9baa049e65c..29009ee6235 100644
--- a/src/main/gitlab/issues.test.ts
+++ b/src/main/gitlab/issues.test.ts
@@ -340,6 +340,37 @@ describe('gitlab issue operations', () => {
     )
   })
 
+  // Why: `glab issue update` has no --hostname flag either, so field edits on an
+  // SSH workspace must carry the host in GITLAB_HOST (#12193).
+  it('updateIssue edits fields through GITLAB_HOST on an SSH workspace', async () => {
+    const projectRef = { host: 'gitlab.example.internal', path: 'stablyai/orca' }
+    glabExecFileAsyncMock.mockResolvedValueOnce({ stdout: '' })
+
+    await expect(
+      updateIssue('/repo-root', 5, { title: 'Renamed' }, undefined, 'conn-1', projectRef)
+    ).resolves.toEqual({ ok: true })
+
+    const [args, options] = glabExecFileAsyncMock.mock.calls[0]
+    expect(args.slice(0, 2)).toEqual(['issue', 'update'])
+    expect(args).not.toContain('--hostname')
+    expect(options.env?.GITLAB_HOST).toBe('gitlab.example.internal')
+  })
+
+  // Why: `glab issue close` has no --hostname flag; a self-hosted instance is
+  // only reachable through GITLAB_HOST (#12193).
+  it('updateIssue closes through GITLAB_HOST on an SSH workspace', async () => {
+    const projectRef = { host: 'gitlab.example.internal', path: 'stablyai/orca' }
+    glabExecFileAsyncMock.mockResolvedValueOnce({ stdout: '' })
+
+    await expect(
+      updateIssue('/repo-root', 5, { state: 'closed' }, undefined, 'conn-1', projectRef)
+    ).resolves.toEqual({ ok: true })
+
+    const [args, options] = glabExecFileAsyncMock.mock.calls[0]
+    expect(args).toEqual(['issue', 'close', '5', '-R', 'stablyai/orca'])
+    expect(options.env?.GITLAB_HOST).toBe('gitlab.example.internal')
+  })
+
   it("updateIssue treats 'already closed' as a no-op", async () => {
     getIssueProjectRefMock.mockResolvedValueOnce({ host: 'gitlab.com', path: 'stablyai/orca' })
     glabExecFileAsyncMock.mockRejectedValueOnce(new Error('Issue is already closed'))
diff --git a/src/main/gitlab/merge-request-creation-lookup.ts b/src/main/gitlab/merge-request-creation-lookup.ts
index e5c8303ce1a..256348ad976 100644
--- a/src/main/gitlab/merge-request-creation-lookup.ts
+++ b/src/main/gitlab/merge-request-creation-lookup.ts
@@ -4,7 +4,7 @@ import {
 } from '../source-control/hosted-review-git-options'
 import {
   glabExecFileAsync,
-  glabHostnameArgs,
+  glabHostEnvOptions,
   glabRepoExecOptions,
   type ProjectRef
 } from './gl-utils'
@@ -65,12 +65,12 @@ export async function findOpenMRByHeadBase(args: {
       '--per-page',
       '2',
       '--output',
-      'json',
-      ...glabHostnameArgs(args.projectRef, args.connectionId)
+      'json'
     ],
     {
       ...glabRepoExecOptions(args.repoPath, args.connectionId),
-      ...(args.connectionId ? {} : getHostedReviewLocalGitOptions(args.options))
+      ...(args.connectionId ? {} : getHostedReviewLocalGitOptions(args.options)),
+      ...glabHostEnvOptions(args.projectRef, args.connectionId)
     }
   )
   const list = JSON.parse(stdout) as {
diff --git a/src/main/gitlab/merge-request-creation.test.ts b/src/main/gitlab/merge-request-creation.test.ts
index c5fc6e06970..6efdbd45d82 100644
--- a/src/main/gitlab/merge-request-creation.test.ts
+++ b/src/main/gitlab/merge-request-creation.test.ts
@@ -4,6 +4,7 @@ const {
   getProjectSlugMock,
   glabExecFileAsyncMock,
   glabHostnameArgsMock,
+  glabHostEnvOptionsMock,
   glabRepoExecOptionsMock,
   acquireMock,
   releaseMock,
@@ -12,6 +13,9 @@ const {
   getProjectSlugMock: vi.fn(),
   glabExecFileAsyncMock: vi.fn(),
   glabHostnameArgsMock: vi.fn((projectRef: { host: string }) => ['--hostname', projectRef.host]),
+  glabHostEnvOptionsMock: vi.fn((projectRef: { host: string }, connectionId?: string | null) =>
+    connectionId ? { env: { GITLAB_HOST: projectRef.host } } : {}
+  ),
   glabRepoExecOptionsMock: vi.fn((repoPath: string, connectionId?: string | null) =>
     connectionId ? {} : { cwd: repoPath }
   ),
@@ -29,6 +33,7 @@ vi.mock('./gl-utils', () => ({
   release: releaseMock,
   glabExecFileAsync: glabExecFileAsyncMock,
   glabHostnameArgs: glabHostnameArgsMock,
+  glabHostEnvOptions: glabHostEnvOptionsMock,
   glabRepoExecOptions: glabRepoExecOptionsMock
 }))
 
@@ -43,6 +48,7 @@ describe('createGitLabMergeRequest', () => {
     getProjectSlugMock.mockReset()
     glabExecFileAsyncMock.mockReset()
     glabHostnameArgsMock.mockClear()
+    glabHostEnvOptionsMock.mockClear()
     glabRepoExecOptionsMock.mockClear()
     acquireMock.mockReset()
     releaseMock.mockReset()
@@ -94,12 +100,15 @@ describe('createGitLabMergeRequest', () => {
         '--draft'
       ])
     )
-    expect(args).toEqual(expect.arrayContaining(['--hostname', 'gitlab.com']))
+    // Why: a local workspace resolves the host from cwd, so neither the flag
+    // nor the env override belongs on the command.
+    expect(args).not.toContain('--hostname')
     expect(options).toMatchObject({
       cwd: '/repo-root',
       timeout: 60_000,
       idempotent: false
     })
+    expect(options.env).toBeUndefined()
     expect(acquireMock).toHaveBeenCalledOnce()
     expect(releaseMock).toHaveBeenCalledOnce()
   })
@@ -268,4 +277,69 @@ describe('createGitLabMergeRequest', () => {
       ])
     )
   })
+
+  // Why: `glab mr create` has no --hostname flag either, so an SSH workspace
+  // has to reach its instance through GITLAB_HOST (#12193).
+  it('creates a merge request through GITLAB_HOST on an SSH workspace', async () => {
+    getProjectSlugMock.mockResolvedValue({ host: 'gitlab.example.internal', path: 'acme/widgets' })
+    glabExecFileAsyncMock.mockResolvedValueOnce({
+      stdout: JSON.stringify({
+        iid: 51,
+        web_url: 'https://gitlab.example.internal/acme/widgets/-/merge_requests/51'
+      }),
+      stderr: ''
+    })
+
+    await expect(
+      createGitLabMergeRequest(
+        '/remote/repo-root',
+        {
+          provider: 'gitlab',
+          base: 'main',
+          head: 'feature/ssh-host',
+          title: 'SSH host MR'
+        },
+        'ssh:ssh-1'
+      )
+    ).resolves.toMatchObject({ ok: true, number: 51 })
+
+    const [args, options] = glabExecFileAsyncMock.mock.calls[0]
+    expect(args.slice(0, 2)).toEqual(['mr', 'create'])
+    expect(args).not.toContain('--hostname')
+    expect(options.env?.GITLAB_HOST).toBe('gitlab.example.internal')
+  })
+
+  // Why: `glab mr list` has no --hostname flag, so the duplicate lookup has to
+  // reach a self-hosted instance through GITLAB_HOST instead (#12193).
+  it('looks up an existing merge request through GITLAB_HOST on an SSH workspace', async () => {
+    glabExecFileAsyncMock
+      .mockRejectedValueOnce(new Error('merge request already exists'))
+      .mockResolvedValueOnce({
+        stdout: JSON.stringify([
+          {
+            iid: 77,
+            web_url: 'https://gitlab.example.internal/acme/widgets/-/merge_requests/77'
+          }
+        ]),
+        stderr: ''
+      })
+    getProjectSlugMock.mockResolvedValue({ host: 'gitlab.example.internal', path: 'acme/widgets' })
+
+    await expect(
+      createGitLabMergeRequest(
+        '/repo-root',
+        {
+          provider: 'gitlab',
+          base: 'main',
+          head: 'feature/existing',
+          title: 'Existing MR'
+        },
+        'ssh:ssh-1'
+      )
+    ).resolves.toMatchObject({ ok: false, code: 'already_exists' })
+
+    const [args, options] = glabExecFileAsyncMock.mock.calls[1]
+    expect(args).not.toContain('--hostname')
+    expect(options.env?.GITLAB_HOST).toBe('gitlab.example.internal')
+  })
 })
diff --git a/src/main/gitlab/merge-request-creation.ts b/src/main/gitlab/merge-request-creation.ts
index 8d0fc520802..57153fb40ae 100644
--- a/src/main/gitlab/merge-request-creation.ts
+++ b/src/main/gitlab/merge-request-creation.ts
@@ -18,7 +18,7 @@ import { getProjectSlug } from './client'
 import {
   acquire,
   glabExecFileAsync,
-  glabHostnameArgs,
+  glabHostEnvOptions,
   glabRepoExecOptions,
   release
 } from './gl-utils'
@@ -188,8 +188,7 @@ export async function createGitLabMergeRequest(
       title,
       '--description',
       body,
-      '--yes',
-      ...glabHostnameArgs(projectRef, connectionId)
+      '--yes'
     ]
     if (head) {
       createArgs.push('--source-branch', head)
@@ -201,6 +200,7 @@ export async function createGitLabMergeRequest(
       const { stdout } = await glabExecFileAsync(createArgs, {
         ...glabRepoExecOptions(repoPath, connectionId),
         ...(connectionId ? {} : getHostedReviewLocalGitOptions(options)),
+        ...glabHostEnvOptions(projectRef, connectionId),
         timeout: 60_000,
         idempotent: false
       })
diff --git a/src/main/gitlab/merge-request-state-mutations.ts b/src/main/gitlab/merge-request-state-mutations.ts
index fb5d33bb670..7aa70ceb5b0 100644
--- a/src/main/gitlab/merge-request-state-mutations.ts
+++ b/src/main/gitlab/merge-request-state-mutations.ts
@@ -1,7 +1,7 @@
 import type { IssueSourcePreference } from '../../shared/repo-types'
 import {
   acquire,
-  glabHostnameArgs,
+  glabHostEnvOptions,
   glabRepoExecOptions,
   glabExecFileAsync,
   release,
@@ -26,17 +26,10 @@ export async function closeMR(
     async (projectRef, repoFlag) => {
       await acquire()
       try {
-        await glabExecFileAsync(
-          [
-            'mr',
-            'close',
-            String(iid),
-            '-R',
-            repoFlag,
-            ...glabHostnameArgs(projectRef, connectionId)
-          ],
-          glabRepoExecOptions(repoPath, connectionId, localGitOptions)
-        )
+        await glabExecFileAsync(['mr', 'close', String(iid), '-R', repoFlag], {
+          ...glabRepoExecOptions(repoPath, connectionId, localGitOptions),
+          ...glabHostEnvOptions(projectRef, connectionId)
+        })
         return { ok: true }
       } catch (err) {
         const msg = err instanceof Error ? err.message : String(err)
@@ -70,17 +63,10 @@ export async function reopenMR(
     async (projectRef, repoFlag) => {
       await acquire()
       try {
-        await glabExecFileAsync(
-          [
-            'mr',
-            'reopen',
-            String(iid),
-            '-R',
-            repoFlag,
-            ...glabHostnameArgs(projectRef, connectionId)
-          ],
-          glabRepoExecOptions(repoPath, connectionId, localGitOptions)
-        )
+        await glabExecFileAsync(['mr', 'reopen', String(iid), '-R', repoFlag], {
+          ...glabRepoExecOptions(repoPath, connectionId, localGitOptions),
+          ...glabHostEnvOptions(projectRef, connectionId)
+        })
         return { ok: true }
       } catch (err) {
         const msg = err instanceof Error ? err.message : String(err)
@@ -118,17 +104,11 @@ export async function mergeMR(
         const methodFlag =
           method === 'squash' ? ['--squash'] : method === 'rebase' ? ['--rebase'] : []
         await glabExecFileAsync(
-          [
-            'mr',
-            'merge',
-            String(iid),
-            '-R',
-            repoFlag,
-            '--yes',
-            ...methodFlag,
-            ...glabHostnameArgs(projectRef, connectionId)
-          ],
-          glabRepoExecOptions(repoPath, connectionId, localGitOptions)
+          ['mr', 'merge', String(iid), '-R', repoFlag, '--yes', ...methodFlag],
+          {
+            ...glabRepoExecOptions(repoPath, connectionId, localGitOptions),
+            ...glabHostEnvOptions(projectRef, connectionId)
+          }
         )
         return { ok: true }
       } catch (err) {