diff --git a/pkg/cmd/extensions/command.go b/pkg/cmd/extensions/command.go
index c7fc031da..7e6644900 100644
--- a/pkg/cmd/extensions/command.go
+++ b/pkg/cmd/extensions/command.go
@@ -43,7 +43,7 @@ func NewCmdExtensions(f *cmdutil.Factory) *cobra.Command {
 				if len(cmds) == 0 {
 					return errors.New("no extensions installed")
 				}
-				// cs := io.ColorScheme()
+				cs := io.ColorScheme()
 				t := utils.NewTablePrinter(io)
 				for _, c := range cmds {
 					var repo string
@@ -55,8 +55,11 @@ func NewCmdExtensions(f *cmdutil.Factory) *cobra.Command {
 
 					t.AddField(fmt.Sprintf("gh %s", c.Name()), nil, nil)
 					t.AddField(repo, nil, nil)
-					// TODO: add notice about available update
-					//t.AddField("Update available", nil, cs.Green)
+					var updateAvailable string
+					if c.UpdateAvailable() {
+						updateAvailable = "Update available"
+					}
+					t.AddField(updateAvailable, nil, cs.Green)
 					t.EndRow()
 				}
 				return t.Render()
diff --git a/pkg/cmd/extensions/command_test.go b/pkg/cmd/extensions/command_test.go
index f67664eaa..ac173f3c8 100644
--- a/pkg/cmd/extensions/command_test.go
+++ b/pkg/cmd/extensions/command_test.go
@@ -146,6 +146,21 @@ func TestNewCmdExtensions(t *testing.T) {
 			isTTY:      false,
 			wantStdout: "",
 		},
+		{
+			name: "list extensions",
+			args: []string{"list"},
+			managerStubs: func(em *extensions.ExtensionManagerMock) func(*testing.T) {
+				em.ListFunc = func() []extensions.Extension {
+					ex1 := &Extension{path: "cli/gh-test", url: "https://github.com/cli/gh-test", updateAvailable: false}
+					ex2 := &Extension{path: "cli/gh-test2", url: "https://github.com/cli/gh-test2", updateAvailable: true}
+					return []extensions.Extension{ex1, ex2}
+				}
+				return func(t *testing.T) {
+					assert.Equal(t, 1, len(em.ListCalls()))
+				}
+			},
+			wantStdout: "gh test\tcli/gh-test\t\ngh test2\tcli/gh-test2\tUpdate available\n",
+		},
 	}
 
 	for _, tt := range tests {
diff --git a/pkg/cmd/extensions/extension.go b/pkg/cmd/extensions/extension.go
index 8fa07e7cf..c3a391f6f 100644
--- a/pkg/cmd/extensions/extension.go
+++ b/pkg/cmd/extensions/extension.go
@@ -8,8 +8,9 @@ import (
 )
 
 type Extension struct {
-	path string
-	url  string
+	path            string
+	url             string
+	updateAvailable bool
 }
 
 func (e *Extension) Name() string {
@@ -40,3 +41,7 @@ func (e *Extension) IsLocal() bool {
 	}
 	return false
 }
+
+func (e *Extension) UpdateAvailable() bool {
+	return e.updateAvailable
+}
diff --git a/pkg/cmd/extensions/manager.go b/pkg/cmd/extensions/manager.go
index ff6452657..bbca3395e 100644
--- a/pkg/cmd/extensions/manager.go
+++ b/pkg/cmd/extensions/manager.go
@@ -87,34 +87,63 @@ func (m *Manager) list(includeMetadata bool) []extensions.Extension {
 	if err != nil {
 		return nil
 	}
-
-	var gitExe string
-	if includeMetadata {
-		gitExe, _ = m.lookPath("git")
-	}
-
 	var results []extensions.Extension
 	for _, f := range entries {
 		if !strings.HasPrefix(f.Name(), "gh-") || !(f.IsDir() || f.Mode()&os.ModeSymlink != 0) {
 			continue
 		}
-		var remoteURL string
-		if gitExe != "" {
-			stdout := bytes.Buffer{}
-			cmd := m.newCommand(gitExe, "--git-dir="+filepath.Join(dir, f.Name(), ".git"), "config", "remote.origin.url")
-			cmd.Stdout = &stdout
-			if err := cmd.Run(); err == nil {
-				remoteURL = strings.TrimSpace(stdout.String())
-			}
+		var remoteUrl string
+		var updateAvailable bool
+		if includeMetadata {
+			remoteUrl = m.getRemoteUrl(f.Name())
+			updateAvailable = m.checkUpdateAvailable(f.Name())
 		}
 		results = append(results, &Extension{
-			path: filepath.Join(dir, f.Name(), f.Name()),
-			url:  remoteURL,
+			path:            filepath.Join(dir, f.Name(), f.Name()),
+			url:             remoteUrl,
+			updateAvailable: updateAvailable,
 		})
 	}
 	return results
 }
 
+func (m *Manager) getRemoteUrl(extension string) string {
+	gitExe, err := m.lookPath("git")
+	if err != nil {
+		return ""
+	}
+	dir := m.installDir()
+	gitDir := "--git-dir=" + filepath.Join(dir, extension, ".git")
+	cmd := m.newCommand(gitExe, gitDir, "config", "remote.origin.url")
+	url, err := cmd.Output()
+	if err != nil {
+		return ""
+	}
+	return strings.TrimSpace(string(url))
+}
+
+func (m *Manager) checkUpdateAvailable(extension string) bool {
+	gitExe, err := m.lookPath("git")
+	if err != nil {
+		return false
+	}
+	dir := m.installDir()
+	gitDir := "--git-dir=" + filepath.Join(dir, extension, ".git")
+	cmd := m.newCommand(gitExe, gitDir, "ls-remote", "origin", "HEAD")
+	lsRemote, err := cmd.Output()
+	if err != nil {
+		return false
+	}
+	remoteSha := bytes.SplitN(lsRemote, []byte("\t"), 2)[0]
+	cmd = m.newCommand(gitExe, gitDir, "rev-parse", "HEAD")
+	localSha, err := cmd.Output()
+	if err != nil {
+		return false
+	}
+	localSha = bytes.TrimSpace(localSha)
+	return !bytes.Equal(remoteSha, localSha)
+}
+
 func (m *Manager) InstallLocal(dir string) error {
 	name := filepath.Base(dir)
 	targetDir := filepath.Join(m.installDir(), name)
diff --git a/pkg/extensions/extension.go b/pkg/extensions/extension.go
index da915463a..4007e7d28 100644
--- a/pkg/extensions/extension.go
+++ b/pkg/extensions/extension.go
@@ -10,6 +10,7 @@ type Extension interface {
 	Path() string
 	URL() string
 	IsLocal() bool
+	UpdateAvailable() bool
 }
 
 //go:generate moq -out manager_mock.go . ExtensionManager
diff --git a/pkg/extensions/extension_mock.go b/pkg/extensions/extension_mock.go
index 8fe35c1f6..17e2a3f6b 100644
--- a/pkg/extensions/extension_mock.go
+++ b/pkg/extensions/extension_mock.go
@@ -29,6 +29,9 @@ var _ Extension = &ExtensionMock{}
 // 			URLFunc: func() string {
 // 				panic("mock out the URL method")
 // 			},
+// 			UpdateAvailableFunc: func() bool {
+// 				panic("mock out the UpdateAvailable method")
+// 			},
 // 		}
 //
 // 		// use mockedExtension in code that requires Extension
@@ -48,6 +51,9 @@ type ExtensionMock struct {
 	// URLFunc mocks the URL method.
 	URLFunc func() string
 
+	// UpdateAvailableFunc mocks the UpdateAvailable method.
+	UpdateAvailableFunc func() bool
+
 	// calls tracks calls to the methods.
 	calls struct {
 		// IsLocal holds details about calls to the IsLocal method.
@@ -62,11 +68,15 @@ type ExtensionMock struct {
 		// URL holds details about calls to the URL method.
 		URL []struct {
 		}
+		// UpdateAvailable holds details about calls to the UpdateAvailable method.
+		UpdateAvailable []struct {
+		}
 	}
-	lockIsLocal sync.RWMutex
-	lockName    sync.RWMutex
-	lockPath    sync.RWMutex
-	lockURL     sync.RWMutex
+	lockIsLocal         sync.RWMutex
+	lockName            sync.RWMutex
+	lockPath            sync.RWMutex
+	lockURL             sync.RWMutex
+	lockUpdateAvailable sync.RWMutex
 }
 
 // IsLocal calls IsLocalFunc.
@@ -172,3 +182,29 @@ func (mock *ExtensionMock) URLCalls() []struct {
 	mock.lockURL.RUnlock()
 	return calls
 }
+
+// UpdateAvailable calls UpdateAvailableFunc.
+func (mock *ExtensionMock) UpdateAvailable() bool {
+	if mock.UpdateAvailableFunc == nil {
+		panic("ExtensionMock.UpdateAvailableFunc: method is nil but Extension.UpdateAvailable was just called")
+	}
+	callInfo := struct {
+	}{}
+	mock.lockUpdateAvailable.Lock()
+	mock.calls.UpdateAvailable = append(mock.calls.UpdateAvailable, callInfo)
+	mock.lockUpdateAvailable.Unlock()
+	return mock.UpdateAvailableFunc()
+}
+
+// UpdateAvailableCalls gets all the calls that were made to UpdateAvailable.
+// Check the length with:
+//     len(mockedExtension.UpdateAvailableCalls())
+func (mock *ExtensionMock) UpdateAvailableCalls() []struct {
+} {
+	var calls []struct {
+	}
+	mock.lockUpdateAvailable.RLock()
+	calls = mock.calls.UpdateAvailable
+	mock.lockUpdateAvailable.RUnlock()
+	return calls
+}