diff --git a/examples/flutter_gallery/lib/demo/animation/widgets.dart b/examples/flutter_gallery/lib/demo/animation/widgets.dart
index c8ca06c5936..08bbfd2b4a0 100644
--- a/examples/flutter_gallery/lib/demo/animation/widgets.dart
+++ b/examples/flutter_gallery/lib/demo/animation/widgets.dart
@@ -19,23 +19,27 @@ class SectionCard extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    return new DecoratedBox(
-      decoration: new BoxDecoration(
-        gradient: new LinearGradient(
-          begin: Alignment.centerLeft,
-          end: Alignment.centerRight,
-          colors: <Color>[
-            section.leftColor,
-            section.rightColor,
-          ],
+    return new Semantics(
+      label: section.title,
+      button: true,
+      child: new DecoratedBox(
+        decoration: new BoxDecoration(
+          gradient: new LinearGradient(
+            begin: Alignment.centerLeft,
+            end: Alignment.centerRight,
+            colors: <Color>[
+              section.leftColor,
+              section.rightColor,
+            ],
+          ),
+        ),
+        child: new Image.asset(
+          section.backgroundAsset,
+          package: section.backgroundAssetPackage,
+          color: const Color.fromRGBO(255, 255, 255, 0.075),
+          colorBlendMode: BlendMode.modulate,
+          fit: BoxFit.cover,
         ),
-      ),
-      child: new Image.asset(
-        section.backgroundAsset,
-        package: section.backgroundAssetPackage,
-        color: const Color.fromRGBO(255, 255, 255, 0.075),
-        colorBlendMode: BlendMode.modulate,
-        fit: BoxFit.cover,
       ),
     );
   }
diff --git a/examples/flutter_gallery/lib/demo/cupertino/cupertino_navigation_demo.dart b/examples/flutter_gallery/lib/demo/cupertino/cupertino_navigation_demo.dart
index 327f1db51f7..9990dc7ce1e 100644
--- a/examples/flutter_gallery/lib/demo/cupertino/cupertino_navigation_demo.dart
+++ b/examples/flutter_gallery/lib/demo/cupertino/cupertino_navigation_demo.dart
@@ -107,6 +107,7 @@ class ExitButton extends StatelessWidget {
       child: const Tooltip(
         message: 'Back',
         child: const Text('Exit'),
+        excludeFromSemantics: true,
       ),
       onPressed: () {
         // The demo is on the root navigator.
diff --git a/examples/flutter_gallery/lib/demo/material/buttons_demo.dart b/examples/flutter_gallery/lib/demo/material/buttons_demo.dart
index ebf98ff245b..cf58a49052e 100644
--- a/examples/flutter_gallery/lib/demo/material/buttons_demo.dart
+++ b/examples/flutter_gallery/lib/demo/material/buttons_demo.dart
@@ -218,14 +218,20 @@ class _ButtonsDemoState extends State<ButtonsDemo> {
         mainAxisSize: MainAxisSize.min,
         children: <Widget>[
           new IconButton(
-            icon: const Icon(Icons.thumb_up),
+            icon: const Icon(
+              Icons.thumb_up,
+              semanticLabel: 'Thumbs up',
+            ),
             onPressed: () {
               setState(() => iconButtonToggle = !iconButtonToggle);
             },
             color: iconButtonToggle ? Theme.of(context).primaryColor : null,
           ),
           const IconButton(
-            icon: const Icon(Icons.thumb_up),
+            icon: const Icon(
+              Icons.thumb_up,
+              semanticLabel: 'Thumbs up',
+            ),
             onPressed: null,
           )
         ]
diff --git a/examples/flutter_gallery/lib/demo/material/icons_demo.dart b/examples/flutter_gallery/lib/demo/material/icons_demo.dart
index 1b7de49d5e2..07f4dd04028 100644
--- a/examples/flutter_gallery/lib/demo/material/icons_demo.dart
+++ b/examples/flutter_gallery/lib/demo/material/icons_demo.dart
@@ -108,21 +108,24 @@ class _IconsDemoCard extends StatelessWidget {
     return new Card(
       child: new DefaultTextStyle(
         style: textStyle,
-        child: new Table(
-          defaultVerticalAlignment: TableCellVerticalAlignment.middle,
-          children: <TableRow> [
-            new TableRow(
-              children: <Widget> [
-                _centeredText('Size'),
-                _centeredText('Enabled'),
-                _centeredText('Disabled'),
-              ]
-            ),
-            _buildIconRow(18.0),
-            _buildIconRow(24.0),
-            _buildIconRow(36.0),
-            _buildIconRow(48.0),
-          ],
+        child: new Semantics(
+          explicitChildNodes: true,
+          child: new Table(
+            defaultVerticalAlignment: TableCellVerticalAlignment.middle,
+            children: <TableRow> [
+              new TableRow(
+                children: <Widget> [
+                  _centeredText('Size'),
+                  _centeredText('Enabled'),
+                  _centeredText('Disabled'),
+                ]
+              ),
+              _buildIconRow(18.0),
+              _buildIconRow(24.0),
+              _buildIconRow(36.0),
+              _buildIconRow(48.0),
+            ],
+          ),
         ),
       ),
     );
diff --git a/examples/flutter_gallery/lib/demo/material/persistent_bottom_sheet_demo.dart b/examples/flutter_gallery/lib/demo/material/persistent_bottom_sheet_demo.dart
index 1f2d55302b2..2fb695a45ed 100644
--- a/examples/flutter_gallery/lib/demo/material/persistent_bottom_sheet_demo.dart
+++ b/examples/flutter_gallery/lib/demo/material/persistent_bottom_sheet_demo.dart
@@ -76,7 +76,10 @@ class _PersistentBottomSheetDemoState extends State<PersistentBottomSheetDemo> {
       floatingActionButton: new FloatingActionButton(
         onPressed: _showMessage,
         backgroundColor: Colors.redAccent,
-        child: const Icon(Icons.add)
+        child: const Icon(
+          Icons.add,
+          semanticLabel: 'Add',
+        ),
       ),
       body: new Center(
         child: new RaisedButton(
diff --git a/examples/flutter_gallery/lib/gallery/demo.dart b/examples/flutter_gallery/lib/gallery/demo.dart
index a18d0d9c324..c6e477ce610 100644
--- a/examples/flutter_gallery/lib/gallery/demo.dart
+++ b/examples/flutter_gallery/lib/gallery/demo.dart
@@ -154,7 +154,10 @@ class FullScreenCodeDialogState extends State<FullScreenCodeDialog> {
     return new Scaffold(
       appBar: new AppBar(
         leading: new IconButton(
-          icon: const Icon(Icons.clear),
+          icon: const Icon(
+            Icons.clear,
+            semanticLabel: 'Close',
+          ),
           onPressed: () { Navigator.pop(context); }
         ),
         title: const Text('Example code')
diff --git a/examples/flutter_gallery/lib/gallery/drawer.dart b/examples/flutter_gallery/lib/gallery/drawer.dart
index 1089224c504..5a4c0a2ef33 100644
--- a/examples/flutter_gallery/lib/gallery/drawer.dart
+++ b/examples/flutter_gallery/lib/gallery/drawer.dart
@@ -52,51 +52,54 @@ class _GalleryDrawerHeaderState extends State<GalleryDrawerHeader> {
   Widget build(BuildContext context) {
     final double systemTopPadding = MediaQuery.of(context).padding.top;
 
-    return new DrawerHeader(
-      decoration: new FlutterLogoDecoration(
-        margin: new EdgeInsets.fromLTRB(12.0, 12.0 + systemTopPadding, 12.0, 12.0),
-        style: _logoHasName ? _logoHorizontal ? FlutterLogoStyle.horizontal
-                                              : FlutterLogoStyle.stacked
-                                              : FlutterLogoStyle.markOnly,
-        lightColor: _logoColor.shade400,
-        darkColor: _logoColor.shade900,
-        textColor: widget.light ? const Color(0xFF616161) : const Color(0xFF9E9E9E),
+    return new Semantics(
+      label: 'Flutter',
+      child: new DrawerHeader(
+        decoration: new FlutterLogoDecoration(
+          margin: new EdgeInsets.fromLTRB(12.0, 12.0 + systemTopPadding, 12.0, 12.0),
+          style: _logoHasName ? _logoHorizontal ? FlutterLogoStyle.horizontal
+                                                : FlutterLogoStyle.stacked
+                                                : FlutterLogoStyle.markOnly,
+          lightColor: _logoColor.shade400,
+          darkColor: _logoColor.shade900,
+          textColor: widget.light ? const Color(0xFF616161) : const Color(0xFF9E9E9E),
+        ),
+        duration: const Duration(milliseconds: 750),
+        child: new GestureDetector(
+          onLongPress: () {
+            setState(() {
+              _logoHorizontal = !_logoHorizontal;
+              if (!_logoHasName)
+                _logoHasName = true;
+            });
+          },
+          onTap: () {
+            setState(() {
+              _logoHasName = !_logoHasName;
+            });
+          },
+          onDoubleTap: () {
+            setState(() {
+              final List<MaterialColor> options = <MaterialColor>[];
+              if (_logoColor != Colors.blue)
+                options.addAll(<MaterialColor>[Colors.blue, Colors.blue, Colors.blue, Colors.blue, Colors.blue, Colors.blue, Colors.blue]);
+              if (_logoColor != Colors.amber)
+                options.addAll(<MaterialColor>[Colors.amber, Colors.amber, Colors.amber]);
+              if (_logoColor != Colors.red)
+                options.addAll(<MaterialColor>[Colors.red, Colors.red, Colors.red]);
+              if (_logoColor != Colors.indigo)
+                options.addAll(<MaterialColor>[Colors.indigo, Colors.indigo, Colors.indigo]);
+              if (_logoColor != Colors.pink)
+                options.addAll(<MaterialColor>[Colors.pink]);
+              if (_logoColor != Colors.purple)
+                options.addAll(<MaterialColor>[Colors.purple]);
+              if (_logoColor != Colors.cyan)
+                options.addAll(<MaterialColor>[Colors.cyan]);
+              _logoColor = options[new math.Random().nextInt(options.length)];
+            });
+          }
+        ),
       ),
-      duration: const Duration(milliseconds: 750),
-      child: new GestureDetector(
-        onLongPress: () {
-          setState(() {
-            _logoHorizontal = !_logoHorizontal;
-            if (!_logoHasName)
-              _logoHasName = true;
-          });
-        },
-        onTap: () {
-          setState(() {
-            _logoHasName = !_logoHasName;
-          });
-        },
-        onDoubleTap: () {
-          setState(() {
-            final List<MaterialColor> options = <MaterialColor>[];
-            if (_logoColor != Colors.blue)
-              options.addAll(<MaterialColor>[Colors.blue, Colors.blue, Colors.blue, Colors.blue, Colors.blue, Colors.blue, Colors.blue]);
-            if (_logoColor != Colors.amber)
-              options.addAll(<MaterialColor>[Colors.amber, Colors.amber, Colors.amber]);
-            if (_logoColor != Colors.red)
-              options.addAll(<MaterialColor>[Colors.red, Colors.red, Colors.red]);
-            if (_logoColor != Colors.indigo)
-              options.addAll(<MaterialColor>[Colors.indigo, Colors.indigo, Colors.indigo]);
-            if (_logoColor != Colors.pink)
-              options.addAll(<MaterialColor>[Colors.pink]);
-            if (_logoColor != Colors.purple)
-              options.addAll(<MaterialColor>[Colors.purple]);
-            if (_logoColor != Colors.cyan)
-              options.addAll(<MaterialColor>[Colors.cyan]);
-            _logoColor = options[new math.Random().nextInt(options.length)];
-          });
-        }
-      )
     );
   }
 }
diff --git a/packages/flutter/lib/src/material/floating_action_button.dart b/packages/flutter/lib/src/material/floating_action_button.dart
index 4d9e3f16a54..75fae20700f 100644
--- a/packages/flutter/lib/src/material/floating_action_button.dart
+++ b/packages/flutter/lib/src/material/floating_action_button.dart
@@ -165,10 +165,14 @@ class _FloatingActionButtonState extends State<FloatingActionButton> {
       child: new Container(
         width: widget.mini ? _kSizeMini : _kSize,
         height: widget.mini ? _kSizeMini : _kSize,
-        child: new InkWell(
-          onTap: widget.onPressed,
-          onHighlightChanged: _handleHighlightChanged,
-          child: result,
+        child: new Semantics(
+          button: true,
+          enabled: widget.onPressed != null,
+          child: new InkWell(
+            onTap: widget.onPressed,
+            onHighlightChanged: _handleHighlightChanged,
+            child: result,
+          ),
         ),
       ),
     );
diff --git a/packages/flutter/lib/src/material/icon_button.dart b/packages/flutter/lib/src/material/icon_button.dart
index ed7a69ffd4f..fe833d6feaf 100644
--- a/packages/flutter/lib/src/material/icon_button.dart
+++ b/packages/flutter/lib/src/material/icon_button.dart
@@ -193,6 +193,7 @@ class IconButton extends StatelessWidget {
 
     Widget result = new Semantics(
       button: true,
+      enabled: onPressed != null,
       child: new ConstrainedBox(
         constraints: const BoxConstraints(minWidth: _kMinButtonSize, minHeight: _kMinButtonSize),
         child: new Padding(
diff --git a/packages/flutter/lib/src/material/tooltip.dart b/packages/flutter/lib/src/material/tooltip.dart
index fcc2125cdd3..52900a1ee79 100644
--- a/packages/flutter/lib/src/material/tooltip.dart
+++ b/packages/flutter/lib/src/material/tooltip.dart
@@ -48,12 +48,14 @@ class Tooltip extends StatefulWidget {
     this.padding: const EdgeInsets.symmetric(horizontal: 16.0),
     this.verticalOffset: 24.0,
     this.preferBelow: true,
+    this.excludeFromSemantics: false,
     this.child,
   }) : assert(message != null),
        assert(height != null),
        assert(padding != null),
        assert(verticalOffset != null),
        assert(preferBelow != null),
+       assert(excludeFromSemantics != null),
        super(key: key);
 
   /// The text to display in the tooltip.
@@ -77,6 +79,10 @@ class Tooltip extends StatefulWidget {
   /// direction.
   final bool preferBelow;
 
+  /// Whether the tooltip's [message] should be excluded from the semantics
+  /// tree.
+  final bool excludeFromSemantics;
+
   /// The widget below this widget in the tree.
   ///
   /// {@macro flutter.widgets.child}
@@ -191,7 +197,7 @@ class _TooltipState extends State<Tooltip> with SingleTickerProviderStateMixin {
       onLongPress: _handleLongPress,
       excludeFromSemantics: true,
       child: new Semantics(
-        label: widget.message,
+        label: widget.excludeFromSemantics ? null : widget.message,
         child: widget.child,
       ),
     );
diff --git a/packages/flutter/test/material/date_picker_test.dart b/packages/flutter/test/material/date_picker_test.dart
index 7e7f9974d3b..137907d7902 100644
--- a/packages/flutter/test/material/date_picker_test.dart
+++ b/packages/flutter/test/material/date_picker_test.dart
@@ -573,13 +573,21 @@ void _tests() {
             ],
           ),
           new TestSemantics(
-            flags: <SemanticsFlag>[SemanticsFlag.isButton],
+            flags: <SemanticsFlag>[
+              SemanticsFlag.isButton,
+              SemanticsFlag.hasEnabledState,
+              SemanticsFlag.isEnabled,
+            ],
             actions: <SemanticsAction>[SemanticsAction.tap],
             label: r'Previous month December 2015',
             textDirection: TextDirection.ltr,
           ),
           new TestSemantics(
-            flags: <SemanticsFlag>[SemanticsFlag.isButton],
+            flags: <SemanticsFlag>[
+              SemanticsFlag.isButton,
+              SemanticsFlag.hasEnabledState,
+              SemanticsFlag.isEnabled,
+            ],
             actions: <SemanticsAction>[SemanticsAction.tap],
             label: r'Next month February 2016',
             textDirection: TextDirection.ltr,
diff --git a/packages/flutter/test/material/floating_action_button_test.dart b/packages/flutter/test/material/floating_action_button_test.dart
index 7471b68b87d..e14884effef 100644
--- a/packages/flutter/test/material/floating_action_button_test.dart
+++ b/packages/flutter/test/material/floating_action_button_test.dart
@@ -2,9 +2,14 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+import 'dart:ui';
+
 import 'package:flutter/material.dart';
+import 'package:flutter/rendering.dart';
 import 'package:flutter_test/flutter_test.dart';
 
+import '../widgets/semantics_tester.dart';
+
 void main() {
   testWidgets('Floating Action Button control test', (WidgetTester tester) async {
     bool didPressButton = false;
@@ -132,4 +137,68 @@ void main() {
     await tester.pump();
     expect(tester.takeException().toString(), contains('xyzzy'));
   });
+
+  testWidgets('Floating Action Button semantics (enabled)', (WidgetTester tester) async {
+    final SemanticsTester semantics = new SemanticsTester(tester);
+
+    await tester.pumpWidget(
+      new Directionality(
+        textDirection: TextDirection.ltr,
+        child: new Center(
+          child: new FloatingActionButton(
+            onPressed: () { },
+            child: const Icon(Icons.add, semanticLabel: 'Add'),
+          ),
+        ),
+      ),
+    );
+
+    expect(semantics, hasSemantics(new TestSemantics.root(
+      children: <TestSemantics>[
+        new TestSemantics.rootChild(
+          label: 'Add',
+          flags: <SemanticsFlag>[
+            SemanticsFlag.isButton,
+            SemanticsFlag.hasEnabledState,
+            SemanticsFlag.isEnabled,
+          ],
+          actions: <SemanticsAction>[
+            SemanticsAction.tap
+          ],
+        ),
+      ],
+    ), ignoreTransform: true, ignoreId: true, ignoreRect: true));
+
+    semantics.dispose();
+  });
+
+  testWidgets('Floating Action Button semantics (disabled)', (WidgetTester tester) async {
+    final SemanticsTester semantics = new SemanticsTester(tester);
+
+    await tester.pumpWidget(
+      const Directionality(
+        textDirection: TextDirection.ltr,
+        child: const Center(
+          child: const FloatingActionButton(
+            onPressed: null,
+            child: const Icon(Icons.add, semanticLabel: 'Add'),
+          ),
+        ),
+      ),
+    );
+
+    expect(semantics, hasSemantics(new TestSemantics.root(
+      children: <TestSemantics>[
+        new TestSemantics.rootChild(
+          label: 'Add',
+          flags: <SemanticsFlag>[
+            SemanticsFlag.isButton,
+            SemanticsFlag.hasEnabledState,
+          ],
+        ),
+      ],
+    ), ignoreTransform: true, ignoreId: true, ignoreRect: true));
+
+    semantics.dispose();
+  });
 }
diff --git a/packages/flutter/test/material/icon_button_test.dart b/packages/flutter/test/material/icon_button_test.dart
index 7fff066e7a3..53c75e5f5a8 100644
--- a/packages/flutter/test/material/icon_button_test.dart
+++ b/packages/flutter/test/material/icon_button_test.dart
@@ -275,7 +275,7 @@ void main() {
     await gesture.up();
   });
 
-  testWidgets('IconButton Semantics', (WidgetTester tester) async {
+  testWidgets('IconButton Semantics (enabled)', (WidgetTester tester) async {
     final SemanticsTester semantics = new SemanticsTester(tester);
 
     await tester.pumpWidget(
@@ -291,8 +291,14 @@ void main() {
       children: <TestSemantics>[
         new TestSemantics.rootChild(
           rect: new Rect.fromLTRB(0.0, 0.0, 48.0, 48.0),
-          actions: <SemanticsAction>[SemanticsAction.tap],
-          flags: <SemanticsFlag>[SemanticsFlag.isButton],
+          actions: <SemanticsAction>[
+            SemanticsAction.tap
+          ],
+          flags: <SemanticsFlag>[
+            SemanticsFlag.hasEnabledState,
+            SemanticsFlag.isEnabled,
+            SemanticsFlag.isButton
+          ],
           label: 'link',
         )
       ]
@@ -300,6 +306,34 @@ void main() {
 
     semantics.dispose();
   });
+
+  testWidgets('IconButton Semantics (disabled)', (WidgetTester tester) async {
+    final SemanticsTester semantics = new SemanticsTester(tester);
+
+    await tester.pumpWidget(
+      wrap(
+        child: const IconButton(
+          onPressed: null,
+          icon: const Icon(Icons.link, semanticLabel: 'link'),
+        ),
+      ),
+    );
+
+    expect(semantics, hasSemantics(new TestSemantics.root(
+        children: <TestSemantics>[
+          new TestSemantics.rootChild(
+            rect: new Rect.fromLTRB(0.0, 0.0, 48.0, 48.0),
+            flags: <SemanticsFlag>[
+              SemanticsFlag.hasEnabledState,
+              SemanticsFlag.isButton
+            ],
+            label: 'link',
+          )
+        ]
+    ), ignoreId: true, ignoreTransform: true));
+
+    semantics.dispose();
+  });
 }
 
 Widget wrap({ Widget child }) {
diff --git a/packages/flutter/test/material/tooltip_test.dart b/packages/flutter/test/material/tooltip_test.dart
index 8b0842b9ed2..67b2d327894 100644
--- a/packages/flutter/test/material/tooltip_test.dart
+++ b/packages/flutter/test/material/tooltip_test.dart
@@ -602,4 +602,57 @@ void main() {
     feedback.dispose();
   });
 
+  testWidgets('Semantics included', (WidgetTester tester) async {
+    final SemanticsTester semantics = new SemanticsTester(tester);
+
+    await tester.pumpWidget(
+      new MaterialApp(
+        home: const Center(
+          child: const Tooltip(
+            message: 'Foo',
+            child: const Text('Bar'),
+          ),
+        ),
+      ),
+    );
+
+    expect(semantics, hasSemantics(new TestSemantics.root(
+      children: <TestSemantics>[
+        new TestSemantics.rootChild(
+          label: 'Foo\nBar',
+          textDirection: TextDirection.ltr,
+        ),
+      ],
+    ), ignoreRect: true, ignoreId: true, ignoreTransform: true));
+
+    semantics.dispose();
+  });
+
+  testWidgets('Semantics excluded', (WidgetTester tester) async {
+    final SemanticsTester semantics = new SemanticsTester(tester);
+
+    await tester.pumpWidget(
+      new MaterialApp(
+        home: const Center(
+          child: const Tooltip(
+            message: 'Foo',
+            child: const Text('Bar'),
+            excludeFromSemantics: true,
+          ),
+        ),
+      ),
+    );
+
+    expect(semantics, hasSemantics(new TestSemantics.root(
+      children: <TestSemantics>[
+        new TestSemantics.rootChild(
+          label: 'Bar',
+          textDirection: TextDirection.ltr,
+        ),
+      ],
+    ), ignoreRect: true, ignoreId: true, ignoreTransform: true));
+
+    semantics.dispose();
+  });
+
 }