diff --git a/editor/components/editor-global-keyboard-shortcuts/index.js b/editor/components/editor-global-keyboard-shortcuts/index.js
index f7d23bd410b0e8..63947cc6921840 100644
--- a/editor/components/editor-global-keyboard-shortcuts/index.js
+++ b/editor/components/editor-global-keyboard-shortcuts/index.js
@@ -64,6 +64,7 @@ class EditorGlobalKeyboardShortcuts extends Component {
 		const { hasMultiSelection, clearSelectedBlock } = this.props;
 		if ( hasMultiSelection ) {
 			clearSelectedBlock();
+			window.getSelection().removeAllRanges();
 		}
 	}
 
diff --git a/editor/components/writing-flow/index.js b/editor/components/writing-flow/index.js
index b93ec9ea256e8e..abc3f24f78003a 100644
--- a/editor/components/writing-flow/index.js
+++ b/editor/components/writing-flow/index.js
@@ -1,7 +1,7 @@
 /**
  * External dependencies
  */
-import { overEvery, find, findLast, reverse } from 'lodash';
+import { overEvery, find, findLast, reverse, first, last } from 'lodash';
 
 /**
  * WordPress dependencies
@@ -15,6 +15,7 @@ import {
 	isVerticalEdge,
 	placeCaretAtHorizontalEdge,
 	placeCaretAtVerticalEdge,
+	isEntirelySelected,
 } from '@wordpress/dom';
 import { keycodes } from '@wordpress/utils';
 import { withSelect, withDispatch } from '@wordpress/data';
@@ -32,7 +33,7 @@ import {
  * Module Constants
  */
 
-const { UP, DOWN, LEFT, RIGHT } = keycodes;
+const { UP, DOWN, LEFT, RIGHT, isKeyboardEvent } = keycodes;
 
 /**
  * Given an element, returns true if the element is a tabbable text field, or
@@ -179,7 +180,7 @@ class WritingFlow extends Component {
 	}
 
 	onKeyDown( event ) {
-		const { hasMultiSelection } = this.props;
+		const { hasMultiSelection, onMultiSelect, blocks } = this.props;
 
 		const { keyCode, target } = event;
 		const isUp = keyCode === UP;
@@ -201,6 +202,25 @@ class WritingFlow extends Component {
 		}
 
 		if ( ! isNav ) {
+			// Set immediately before the meta+a combination can be pressed.
+			if ( isKeyboardEvent.primary( event ) ) {
+				this.isEntirelySelected = isEntirelySelected( target );
+			}
+
+			if ( isKeyboardEvent.primary( event, 'a' ) ) {
+				// When the target is contentEditable, selection will already
+				// have been set by TinyMCE earlier in this call stack. We need
+				// check the previous result, otherwise all blocks will be
+				// selected right away.
+				if ( target.isContentEditable ? this.isEntirelySelected : isEntirelySelected( target ) ) {
+					onMultiSelect( first( blocks ), last( blocks ) );
+					event.preventDefault();
+				}
+
+				// Set in case the meta key doesn't get released.
+				this.isEntirelySelected = isEntirelySelected( target );
+			}
+
 			return;
 		}
 
@@ -278,6 +298,7 @@ export default compose( [
 			getFirstMultiSelectedBlockUid,
 			getLastMultiSelectedBlockUid,
 			hasMultiSelection,
+			getBlockOrder,
 		} = select( 'core/editor' );
 
 		const selectedBlockUID = getSelectedBlockUID();
@@ -292,6 +313,7 @@ export default compose( [
 			selectedFirstUid: getFirstMultiSelectedBlockUid(),
 			selectedLastUid: getLastMultiSelectedBlockUid(),
 			hasMultiSelection: hasMultiSelection(),
+			blocks: getBlockOrder(),
 		};
 	} ),
 	withDispatch( ( dispatch ) => {
diff --git a/packages/dom/src/dom.js b/packages/dom/src/dom.js
index f0dbeb5c5ae8f8..40b7c7f08147d9 100644
--- a/packages/dom/src/dom.js
+++ b/packages/dom/src/dom.js
@@ -395,6 +395,40 @@ export function documentHasSelection() {
 	return range && ! range.collapsed;
 }
 
+/**
+ * Check whether the contents of the element have been entirely selected.
+ * Returns true if there is no possibility of selection.
+ *
+ * @param {Element} element The element to check.
+ *
+ * @return {boolean} True if entirely selected, false if not.
+ */
+export function isEntirelySelected( element ) {
+	if ( includes( [ 'INPUT', 'TEXTAREA' ], element.nodeName ) ) {
+		return element.selectionStart === 0 && element.value.length === element.selectionEnd;
+	}
+
+	if ( ! element.isContentEditable ) {
+		return true;
+	}
+
+	const selection = window.getSelection();
+	const range = selection.rangeCount ? selection.getRangeAt( 0 ) : null;
+
+	if ( ! range ) {
+		return true;
+	}
+
+	const { startContainer, endContainer, startOffset, endOffset } = range;
+
+	return (
+		startContainer === element &&
+		endContainer === element &&
+		startOffset === 0 &&
+		endOffset === element.childNodes.length
+	);
+}
+
 /**
  * Given a DOM node, finds the closest scrollable container node.
  *
diff --git a/utils/keycodes.js b/utils/keycodes.js
index 40274e25bfa6ca..a94c824470456f 100644
--- a/utils/keycodes.js
+++ b/utils/keycodes.js
@@ -12,7 +12,7 @@
 /**
  * External dependencies
  */
-import { get, mapValues } from 'lodash';
+import { get, mapValues, includes } from 'lodash';
 
 export const BACKSPACE = 8;
 export const TAB = 9;
@@ -90,3 +90,27 @@ export const displayShortcut = mapValues( modifiers, ( modifier ) => {
 		return shortcut.replace( /⌘\+([A-Z0-9])$/g, '⌘$1' );
 	};
 } );
+
+/**
+ * An object that contains functions to check if a keyboard event matches a
+ * predefined shortcut combination.
+ * E.g. isKeyboardEvent.primary( event, 'm' ) will return true if the event
+ * signals pressing ⌘M.
+ *
+ * @type {Object} Keyed map of functions to match events.
+ */
+export const isKeyboardEvent = mapValues( modifiers, ( getModifiers ) => {
+	return ( event, character, _isMac = isMacOS ) => {
+		const mods = getModifiers( _isMac );
+
+		if ( ! mods.every( ( key ) => event[ `${ key }Key` ] ) ) {
+			return false;
+		}
+
+		if ( ! character ) {
+			return includes( mods, event.key.toLowerCase() );
+		}
+
+		return event.key === character;
+	};
+} );