diff --git a/src/app/components/editor/Editor.tsx b/src/app/components/editor/Editor.tsx
index bd848dd5..b7e6d2fe 100644
--- a/src/app/components/editor/Editor.tsx
+++ b/src/app/components/editor/Editor.tsx
@@ -23,6 +23,9 @@ import { RenderElement, RenderLeaf } from './Elements';
 import { CustomElement } from './slate';
 import * as css from './Editor.css';
 import { toggleKeyboardShortcut } from './keyboard';
+import { useSetting } from '../../state/hooks/settings';
+import { settingsAtom } from '../../state/settings';
+import { composerSpellcheckAttributes } from './spellcheck';
 
 const initialValue: CustomElement[] = [
   {
@@ -90,6 +93,7 @@ export const CustomEditor = forwardRef<HTMLDivElement, CustomEditorProps>(
     },
     ref
   ) => {
+    const [composerSpellcheck] = useSetting(settingsAtom, 'composerSpellcheck');
     const renderElement = useCallback(
       (props: RenderElementProps) => <RenderElement {...props} />,
       []
@@ -146,6 +150,7 @@ export const CustomEditor = forwardRef<HTMLDivElement, CustomEditorProps>(
                 onKeyDown={handleKeydown}
                 onKeyUp={onKeyUp}
                 onPaste={onPaste}
+                {...composerSpellcheckAttributes(composerSpellcheck)}
               />
             </Scroll>
             {after && (
diff --git a/src/app/components/editor/spellcheck.test.ts b/src/app/components/editor/spellcheck.test.ts
new file mode 100644
index 00000000..fa0535cb
--- /dev/null
+++ b/src/app/components/editor/spellcheck.test.ts
@@ -0,0 +1,27 @@
+import { describe, expect, it } from 'vitest';
+import { composerSpellcheckAttributes, defaultComposerSpellcheck } from './spellcheck';
+
+const media = (coarse: boolean) => (query: string) => ({
+  matches: query === '(pointer: coarse)' && coarse,
+});
+
+describe('composer spellcheck default', () => {
+  it('is off when the primary pointer is coarse (phone)', () => {
+    expect(defaultComposerSpellcheck(media(true))).toBe(false);
+  });
+  it('is on for a fine pointer (desktop)', () => {
+    expect(defaultComposerSpellcheck(media(false))).toBe(true);
+  });
+  it('is on when matchMedia is unavailable', () => {
+    expect(defaultComposerSpellcheck(undefined)).toBe(true);
+  });
+});
+
+describe('composer spellcheck attributes', () => {
+  it('off disables both spellcheck and autocorrect', () => {
+    expect(composerSpellcheckAttributes(false)).toEqual({ spellCheck: false, autoCorrect: 'off' });
+  });
+  it('on enables spellcheck and leaves autocorrect to the platform', () => {
+    expect(composerSpellcheckAttributes(true)).toEqual({ spellCheck: true });
+  });
+});
diff --git a/src/app/components/editor/spellcheck.ts b/src/app/components/editor/spellcheck.ts
new file mode 100644
index 00000000..825676ef
--- /dev/null
+++ b/src/app/components/editor/spellcheck.ts
@@ -0,0 +1,11 @@
+/** Touch devices (phones) get the keyboard's own dictionary; desktop gets the browser's. */
+export const defaultComposerSpellcheck = (
+  matchMedia: ((query: string) => { matches: boolean }) | undefined
+): boolean => !matchMedia?.('(pointer: coarse)').matches;
+
+/**
+ * Attributes for the composer's editable. Off must also switch autocorrect off:
+ * spellCheck alone leaves Gboard's suggestion strip and correction modal in place.
+ */
+export const composerSpellcheckAttributes = (enabled: boolean) =>
+  enabled ? ({ spellCheck: true } as const) : ({ spellCheck: false, autoCorrect: 'off' } as const);
diff --git a/src/app/features/settings/general/General.tsx b/src/app/features/settings/general/General.tsx
index b861a060..a51f4175 100644
--- a/src/app/features/settings/general/General.tsx
+++ b/src/app/features/settings/general/General.tsx
@@ -709,6 +709,10 @@ function DateAndTime() {
 
 function Editor() {
   const [enterForNewline, setEnterForNewline] = useSetting(settingsAtom, 'enterForNewline');
+  const [composerSpellcheck, setComposerSpellcheck] = useSetting(
+    settingsAtom,
+    'composerSpellcheck'
+  );
   const [isMarkdown, setIsMarkdown] = useSetting(settingsAtom, 'isMarkdown');
   const [hideActivity, setHideActivity] = useSetting(settingsAtom, 'hideActivity');
 
@@ -724,6 +728,15 @@ function Editor() {
           after={<Switch variant="Primary" value={enterForNewline} onChange={setEnterForNewline} />}
         />
       </SequenceCard>
+      <SequenceCard className={SequenceCardStyle} variant="SurfaceVariant" direction="Column">
+        <SettingTile
+          title="Spellcheck in composer"
+          description="Underline misspelled words while typing. Off by default on touch devices, where the keyboard has its own."
+          after={
+            <Switch variant="Primary" value={composerSpellcheck} onChange={setComposerSpellcheck} />
+          }
+        />
+      </SequenceCard>
       <SequenceCard className={SequenceCardStyle} variant="SurfaceVariant" direction="Column">
         <SettingTile
           title="Markdown Formatting"
diff --git a/src/app/state/settings.ts b/src/app/state/settings.ts
index 6a894350..8df34155 100644
--- a/src/app/state/settings.ts
+++ b/src/app/state/settings.ts
@@ -1,4 +1,5 @@
 import { atom } from 'jotai';
+import { defaultComposerSpellcheck } from '../components/editor/spellcheck';
 
 const STORAGE_KEY = 'settings';
 export type DateFormat =
@@ -30,6 +31,7 @@ export interface Settings {
   isPeopleDrawer: boolean;
   memberSortFilterIndex: number;
   enterForNewline: boolean;
+  composerSpellcheck: boolean;
   messageLayout: MessageLayout;
   messageSpacing: MessageSpacing;
   hideMembershipEvents: boolean;
@@ -64,6 +66,7 @@ const defaultSettings: Settings = {
   isPeopleDrawer: false,
   memberSortFilterIndex: 0,
   enterForNewline: false,
+  composerSpellcheck: defaultComposerSpellcheck(window.matchMedia?.bind(window)),
   messageLayout: 2,
   messageSpacing: '400',
   hideMembershipEvents: false,