Index: src/wp-admin/js/theme.js
===================================================================
--- src/wp-admin/js/theme.js	(revision 27969)
+++ src/wp-admin/js/theme.js	(working copy)
@@ -716,20 +716,28 @@
 	html: themes.template( 'theme-preview' ),
 
 	render: function() {
-		var data = this.model.toJSON();
+		var data = this.model.toJSON(),
+			self = this;
 		this.$el.html( this.html( data ) );
 
 		themes.router.navigate( themes.router.baseUrl( '?theme=' + this.model.get( 'id' ) ), { replace: true } );
 
 		this.$el.fadeIn( 200, function() {
-			$( 'body' ).addClass( 'theme-installer-active full-overlay-active' );
+			$( 'body' )
+				.addClass( 'theme-installer-active full-overlay-active' )
+				.on( 'keyup', function( event ) {
+					// Pressing the escape closes the preview
+					if ( event.keyCode === 27 ) {
+						self.close();
+					}
+				});;
 			$( '.close-full-overlay' ).focus();
 		});
 	},
 
 	close: function() {
 		this.$el.fadeOut( 200, function() {
-			$( 'body' ).removeClass( 'theme-installer-active full-overlay-active' );
+			$( 'body' ).removeClass( 'theme-installer-active full-overlay-active' ).unbind( 'keyup' );
 
 			// Return focus to the theme div
 			if ( themes.focusedTheme ) {