diff --git a/core/block_render_svg_horizontal.js b/core/block_render_svg_horizontal.js
index 4c91f7c112..99fd12dfd9 100644
--- a/core/block_render_svg_horizontal.js
+++ b/core/block_render_svg_horizontal.js
@@ -201,7 +201,8 @@ Blockly.BlockSvg.prototype.updateColour = function() {
   this.svgPath_.setAttribute('stroke', strokeColour);
 
   // Render block fill
-  this.svgPath_.setAttribute('fill', this.getColour());
+  var fillColour = (this.isGlowing_) ? this.getColourSecondary() : this.getColour();
+  this.svgPath_.setAttribute('fill', fillColour);
 
   // Bump every dropdown to change its colour.
   for (var x = 0, input; input = this.inputList[x]; x++) {
diff --git a/core/block_svg.js b/core/block_svg.js
index ce19f26e86..6694aba840 100644
--- a/core/block_svg.js
+++ b/core/block_svg.js
@@ -76,6 +76,13 @@ Blockly.BlockSvg.prototype.width = 0;
  */
 Blockly.BlockSvg.prototype.dragStartXY_ = null;
 
+/**
+ * Whether the block glows as if running.
+ * @type {boolean}
+ * @private
+ */
+Blockly.BlockSvg.prototype.isGlowing_ = false;
+
 /**
  * Constant for identifying rows that are to be rendered inline.
  * Don't collide with Blockly.INPUT_VALUE and friends.
@@ -134,6 +141,15 @@ Blockly.BlockSvg.prototype.unselect = function() {
   Blockly.fireUiEvent(this.workspace.getCanvas(), 'blocklySelectChange');
 };
 
+/**
+ * Glow this block.  Highlight it visually as if it's running.
+ * @param {boolean} isGlowing Whether the block should glow.
+ */
+Blockly.BlockSvg.prototype.setGlow = function(isGlowing) {
+  this.isGlowing_ = isGlowing;
+  this.updateColour();
+};
+
 /**
  * Block's mutator icon (if any).
  * @type {Blockly.Mutator}
diff --git a/core/inject.js b/core/inject.js
index 13d3a04d77..29c936f0a0 100644
--- a/core/inject.js
+++ b/core/inject.js
@@ -279,6 +279,19 @@ Blockly.createDom_ = function(container, options) {
        'k1': 0, 'k2': 1, 'k3': 1, 'k4': 0}, embossFilter);
   options.embossFilterId = embossFilter.id;
 
+  var stackGlowFilter = Blockly.createSvgElement('filter',
+      {'id': 'blocklyStackGlowFilter' + rnd}, defs);
+  Blockly.createSvgElement('feMorphology',
+      {'in': 'SourceAlpha', 'operator': 'dilate', 'radius': 4, 'result': 'outBlur'}, stackGlowFilter);
+  Blockly.createSvgElement('feFlood',
+      {'flood-color': '#05f', 'flood-opacity': '0.9', 'result': 'outColor'}, stackGlowFilter);
+  Blockly.createSvgElement('feComposite',
+      {'in': 'outColor', 'in2': 'outBlur',
+       'operator': 'in', 'result': 'outGlow'}, stackGlowFilter);
+  Blockly.createSvgElement('feComposite',
+      {'in': 'SourceGraphic', 'in2': 'outGlow', 'operator': 'over'}, stackGlowFilter);
+  options.stackGlowFilterId = stackGlowFilter.id;
+
   var disabledPattern = Blockly.createSvgElement('pattern',
       {'id': 'blocklyDisabledPattern' + rnd,
        'patternUnits': 'userSpaceOnUse',
diff --git a/core/workspace_svg.js b/core/workspace_svg.js
index e258a6e15c..c9ff7a4639 100644
--- a/core/workspace_svg.js
+++ b/core/workspace_svg.js
@@ -454,6 +454,22 @@ Blockly.WorkspaceSvg.prototype.highlightBlock = function(id) {
   setTimeout(function() {thisWorkspace.traceOn(true);}, 1);
 };
 
+/**
+ * Glow/unglow a block in the workspace.
+ * @param {?string} id ID of block to find.
+ * @param {boolean} isGlowing Whether to glow the block.
+ */
+Blockly.WorkspaceSvg.prototype.glowBlock = function(id, isGlowing) {
+  var block = null;
+  if (id) {
+    block = Blockly.Block.getById(id);
+    if (!block) {
+      throw 'Tried to glow block that does not exist.';
+    }
+  }
+  block.setGlow(isGlowing);
+};
+
 /**
  * Paste the provided block onto the workspace.
  * @param {!Element} xmlBlock XML block element.