diff --git a/packages/cli/src/ui/components/messages/DiffRenderer.test.tsx b/packages/cli/src/ui/components/messages/DiffRenderer.test.tsx
index 9629b94ba..d2fbecf35 100644
--- a/packages/cli/src/ui/components/messages/DiffRenderer.test.tsx
+++ b/packages/cli/src/ui/components/messages/DiffRenderer.test.tsx
@@ -9,6 +9,7 @@ import { render } from 'ink-testing-library';
 import { DiffRenderer } from './DiffRenderer.js';
 import * as CodeColorizer from '../../utils/CodeColorizer.js';
 import { vi } from 'vitest';
+import type { LoadedSettings } from '../../../config/settings.js';
 
 describe('<OverflowProvider><DiffRenderer /></OverflowProvider>', () => {
   const mockColorizeCode = vi.spyOn(CodeColorizer, 'colorizeCode');
@@ -45,6 +46,7 @@ index 0000000..e69de29
       undefined,
       80,
       undefined,
+      undefined,
     );
   });
 
@@ -73,6 +75,7 @@ index 0000000..e69de29
       undefined,
       80,
       undefined,
+      undefined,
     );
   });
 
@@ -97,6 +100,7 @@ index 0000000..e69de29
       undefined,
       80,
       undefined,
+      undefined,
     );
   });
 
@@ -362,4 +366,86 @@ fileDiff Index: Dockerfile
 2 RUN npm install
 3 RUN npm run build`);
   });
+
+  describe('showLineNumbers setting', () => {
+    const diffContent = `
+diff --git a/test.txt b/test.txt
+index 0000001..0000002 100644
+--- a/test.txt
++++ b/test.txt
+@@ -1,2 +1,2 @@
+-old line 1
++new line 1
+ context line 2
+`;
+
+    it('should show line numbers by default when settings is undefined', () => {
+      const { lastFrame } = render(
+        <OverflowProvider>
+          <DiffRenderer
+            diffContent={diffContent}
+            filename="test.txt"
+            terminalWidth={80}
+          />
+        </OverflowProvider>,
+      );
+      const output = lastFrame();
+      expect(output).toContain('1 -');
+      expect(output).toContain('1 +');
+      expect(output).toContain('2  ');
+    });
+
+    it('should show line numbers when showLineNumbers is true', () => {
+      const mockSettings = {
+        merged: {
+          ui: {
+            showLineNumbers: true,
+          },
+        },
+      } as unknown as LoadedSettings;
+
+      const { lastFrame } = render(
+        <OverflowProvider>
+          <DiffRenderer
+            diffContent={diffContent}
+            filename="test.txt"
+            terminalWidth={80}
+            settings={mockSettings}
+          />
+        </OverflowProvider>,
+      );
+      const output = lastFrame();
+      expect(output).toContain('1 -');
+      expect(output).toContain('1 +');
+      expect(output).toContain('2  ');
+    });
+
+    it('should hide line numbers when showLineNumbers is false', () => {
+      const mockSettings = {
+        merged: {
+          ui: {
+            showLineNumbers: false,
+          },
+        },
+      } as unknown as LoadedSettings;
+
+      const { lastFrame } = render(
+        <OverflowProvider>
+          <DiffRenderer
+            diffContent={diffContent}
+            filename="test.txt"
+            terminalWidth={80}
+            settings={mockSettings}
+          />
+        </OverflowProvider>,
+      );
+      const output = lastFrame();
+      // Line numbers should not be present
+      expect(output).not.toMatch(/^\s*\d+\s*[-+]/m);
+      // But the content should still be there
+      expect(output).toContain('old line 1');
+      expect(output).toContain('new line 1');
+      expect(output).toContain('context line 2');
+    });
+  });
 });
diff --git a/packages/cli/src/ui/components/messages/DiffRenderer.tsx b/packages/cli/src/ui/components/messages/DiffRenderer.tsx
index d962d683b..a3c603227 100644
--- a/packages/cli/src/ui/components/messages/DiffRenderer.tsx
+++ b/packages/cli/src/ui/components/messages/DiffRenderer.tsx
@@ -11,6 +11,7 @@ import { colorizeCode, colorizeLine } from '../../utils/CodeColorizer.js';
 import { MaxSizedBox } from '../shared/MaxSizedBox.js';
 import { theme as semanticTheme } from '../../semantic-colors.js';
 import type { Theme } from '../../themes/theme.js';
+import type { LoadedSettings } from '../../../config/settings.js';
 
 interface DiffLine {
   type: 'add' | 'del' | 'context' | 'hunk' | 'other';
@@ -86,6 +87,7 @@ interface DiffRendererProps {
   availableTerminalHeight?: number;
   terminalWidth: number;
   theme?: Theme;
+  settings?: LoadedSettings;
 }
 
 const DEFAULT_TAB_WIDTH = 4; // Spaces per tab for normalization
@@ -97,6 +99,7 @@ export const DiffRenderer: React.FC<DiffRendererProps> = ({
   availableTerminalHeight,
   terminalWidth,
   theme,
+  settings,
 }) => {
   const screenReaderEnabled = useIsScreenReaderEnabled();
   if (!diffContent || typeof diffContent !== 'string') {
@@ -157,6 +160,7 @@ export const DiffRenderer: React.FC<DiffRendererProps> = ({
       availableTerminalHeight,
       terminalWidth,
       theme,
+      settings,
     );
   } else {
     renderedOutput = renderDiffContent(
@@ -165,6 +169,7 @@ export const DiffRenderer: React.FC<DiffRendererProps> = ({
       tabWidth,
       availableTerminalHeight,
       terminalWidth,
+      settings,
     );
   }
 
@@ -177,6 +182,7 @@ const renderDiffContent = (
   tabWidth = DEFAULT_TAB_WIDTH,
   availableTerminalHeight: number | undefined,
   terminalWidth: number,
+  settings?: LoadedSettings,
 ) => {
   // 1. Normalize whitespace (replace tabs with spaces) *before* further processing
   const normalizedLines = parsedLines.map((line) => ({
@@ -201,6 +207,8 @@ const renderDiffContent = (
     );
   }
 
+  const showLineNumbers = settings?.merged.ui?.showLineNumbers ?? true;
+
   const maxLineNumber = Math.max(
     0,
     ...displayableLines.map((l) => l.oldLine ?? 0),
@@ -299,18 +307,20 @@ const renderDiffContent = (
 
         acc.push(
           <Box key={lineKey} flexDirection="row">
-            <Text
-              color={semanticTheme.text.secondary}
-              backgroundColor={
-                line.type === 'add'
-                  ? semanticTheme.background.diff.added
-                  : line.type === 'del'
-                    ? semanticTheme.background.diff.removed
-                    : undefined
-              }
-            >
-              {gutterNumStr.padStart(gutterWidth)}{' '}
-            </Text>
+            {showLineNumbers && (
+              <Text
+                color={semanticTheme.text.secondary}
+                backgroundColor={
+                  line.type === 'add'
+                    ? semanticTheme.background.diff.added
+                    : line.type === 'del'
+                      ? semanticTheme.background.diff.removed
+                      : undefined
+                }
+              >
+                {gutterNumStr.padStart(gutterWidth)}{' '}
+              </Text>
+            )}
             {line.type === 'context' ? (
               <>
                 <Text>{prefixSymbol} </Text>
diff --git a/packages/cli/src/ui/components/messages/ToolMessage.test.tsx b/packages/cli/src/ui/components/messages/ToolMessage.test.tsx
index 883cdfb89..fa853d876 100644
--- a/packages/cli/src/ui/components/messages/ToolMessage.test.tsx
+++ b/packages/cli/src/ui/components/messages/ToolMessage.test.tsx
@@ -58,10 +58,17 @@ vi.mock('../GeminiRespondingSpinner.js', () => ({
 vi.mock('./DiffRenderer.js', () => ({
   DiffRenderer: function MockDiffRenderer({
     diffContent,
+    settings,
   }: {
     diffContent: string;
+    settings?: unknown;
   }) {
-    return <Text>MockDiff:{diffContent}</Text>;
+    return (
+      <Text>
+        MockDiff:{diffContent}
+        {settings ? ':withSettings' : ''}
+      </Text>
+    );
   },
 }));
 vi.mock('../../utils/MarkdownDisplay.js', () => ({
diff --git a/packages/cli/src/ui/components/messages/ToolMessage.tsx b/packages/cli/src/ui/components/messages/ToolMessage.tsx
index 67e442544..8f5017f52 100644
--- a/packages/cli/src/ui/components/messages/ToolMessage.tsx
+++ b/packages/cli/src/ui/components/messages/ToolMessage.tsx
@@ -30,6 +30,8 @@ import {
   TOOL_STATUS,
 } from '../../constants.js';
 import { theme } from '../../semantic-colors.js';
+import { SettingsContext } from '../../contexts/SettingsContext.js';
+import type { LoadedSettings } from '../../../config/settings.js';
 
 const STATIC_HEIGHT = 1;
 const RESERVED_LINE_COUNT = 5; // for tool name, status, padding etc.
@@ -210,12 +212,14 @@ const DiffResultRenderer: React.FC<{
   data: { fileDiff: string; fileName: string };
   availableHeight?: number;
   childWidth: number;
-}> = ({ data, availableHeight, childWidth }) => (
+  settings?: LoadedSettings;
+}> = ({ data, availableHeight, childWidth, settings }) => (
   <DiffRenderer
     diffContent={data.fileDiff}
     filename={data.fileName}
     availableTerminalHeight={availableHeight}
     terminalWidth={childWidth}
+    settings={settings}
   />
 );
 
@@ -243,6 +247,7 @@ export const ToolMessage: React.FC<ToolMessageProps> = ({
   ptyId,
   config,
 }) => {
+  const settings = React.useContext(SettingsContext);
   const isThisShellFocused =
     (name === SHELL_COMMAND_NAME || name === 'Shell') &&
     status === ToolCallStatus.Executing &&
@@ -349,6 +354,7 @@ export const ToolMessage: React.FC<ToolMessageProps> = ({
                 data={displayRenderer.data}
                 availableHeight={availableHeight}
                 childWidth={childWidth}
+                settings={settings}
               />
             )}
             {displayRenderer.type === 'ansi' && (