diff --git a/core/field_label.js b/core/field_label.js
index 3b8bde5f6..ae1508c02 100644
--- a/core/field_label.js
+++ b/core/field_label.js
@@ -40,22 +40,29 @@ goog.require('Blockly.utils.Size');
  * @param {string=} opt_value The initial value of the field. Should cast to a
  *    string. Defaults to an empty string if null or undefined.
  * @param {string=} opt_class Optional CSS class for the field's text.
+ * @param {Object=} opt_config A map of options used to configure the field.
+ *    See the [field creation documentation]{@link https://developers.google.com/blockly/guides/create-custom-blocks/fields/built-in-fields/label#creation}
+ *    for a list of properties this parameter supports.
  * @extends {Blockly.Field}
  * @constructor
  */
-Blockly.FieldLabel = function(opt_value, opt_class) {
+Blockly.FieldLabel = function(opt_value, opt_class, opt_config) {
   /**
    * The html class name to use for this field.
    * @type {?string}
    * @private
    */
-  this.class_ = opt_class || null;
+  this.class_ = null;
 
   if (opt_value == null) {
     opt_value = '';
   }
   Blockly.FieldLabel.superClass_.constructor.call(
-      this, opt_value, null);
+      this, opt_value, null, opt_config);
+
+  if (!opt_config) {  // If the config was not passed use old configuration.
+    this.class_ = opt_class;
+  }
 
   /**
    * The size of the area rendered by the field.
@@ -77,7 +84,7 @@ Blockly.utils.object.inherits(Blockly.FieldLabel, Blockly.Field);
  */
 Blockly.FieldLabel.fromJson = function(options) {
   var text = Blockly.utils.replaceMessageReferences(options['text']);
-  return new Blockly.FieldLabel(text, options['class']);
+  return new Blockly.FieldLabel(text, null, options);
 };
 
 /**
@@ -88,6 +95,14 @@ Blockly.FieldLabel.fromJson = function(options) {
  */
 Blockly.FieldLabel.prototype.EDITABLE = false;
 
+/**
+ * @override
+ */
+Blockly.FieldLabel.prototype.configure_ = function(config) {
+  Blockly.FieldLabel.superClass_.configure_.call(this, config);
+  this.class_ = config['class'];
+};
+
 /**
  * Create block UI for this label.
  * @package
@@ -114,4 +129,22 @@ Blockly.FieldLabel.prototype.doClassValidation_ = function(opt_newValue) {
   return String(opt_newValue);
 };
 
+/**
+ * Set the css class applied to the field's textElement_.
+ * @param {?string} cssClass The new css class name, or null to remove.
+ */
+Blockly.FieldLabel.prototype.setClass = function(cssClass) {
+  if (this.textElement_) {
+    // This check isn't necessary, but it's faster than letting removeClass
+    // figure it out.
+    if (this.class_) {
+      Blockly.utils.dom.removeClass(this.textElement_, this.class_);
+    }
+    if (cssClass) {
+      Blockly.utils.dom.addClass(this.textElement_, cssClass);
+    }
+  }
+  this.class_ = cssClass;
+};
+
 Blockly.fieldRegistry.register('field_label', Blockly.FieldLabel);
diff --git a/core/field_label_serializable.js b/core/field_label_serializable.js
index 68712402b..2c020519b 100644
--- a/core/field_label_serializable.js
+++ b/core/field_label_serializable.js
@@ -38,13 +38,16 @@ goog.require('Blockly.utils.object');
  * @param {*} opt_value The initial value of the field. Should cast to a
  *    string. Defaults to an empty string if null or undefined.
  * @param {string=} opt_class Optional CSS class for the field's text.
+ * @param {Object=} opt_config A map of options used to configure the field.
+ *    See the [field creation documentation]{@link https://developers.google.com/blockly/guides/create-custom-blocks/fields/built-in-fields/label-serializable#creation}
+ *    for a list of properties this parameter supports.
  * @extends {Blockly.FieldLabel}
  * @constructor
  *
  */
-Blockly.FieldLabelSerializable = function(opt_value, opt_class) {
-  Blockly.FieldLabelSerializable.superClass_.constructor.call(this, opt_value,
-      opt_class);
+Blockly.FieldLabelSerializable = function(opt_value, opt_class, opt_config) {
+  Blockly.FieldLabelSerializable.superClass_.constructor.call(
+      this, opt_value, opt_class, opt_config);
 };
 Blockly.utils.object.inherits(Blockly.FieldLabelSerializable,
     Blockly.FieldLabel);
@@ -59,7 +62,7 @@ Blockly.utils.object.inherits(Blockly.FieldLabelSerializable,
  */
 Blockly.FieldLabelSerializable.fromJson = function(options) {
   var text = Blockly.utils.replaceMessageReferences(options['text']);
-  return new Blockly.FieldLabelSerializable(text, options['class']);
+  return new Blockly.FieldLabelSerializable(text, null, options);
 };
 
 /**
diff --git a/tests/mocha/field_label_serializable_test.js b/tests/mocha/field_label_serializable_test.js
index 09659af1a..07b8544be 100644
--- a/tests/mocha/field_label_serializable_test.js
+++ b/tests/mocha/field_label_serializable_test.js
@@ -28,6 +28,18 @@ suite('Label Serializable Fields', function() {
   function assertValueDefault(labelField) {
     assertValue(labelField, '');
   }
+  function assertHasClass(labelField, cssClass) {
+    labelField.fieldGroup_ = Blockly.utils.dom.createSvgElement('g', {}, null);
+    labelField.initView();
+    chai.assert.isTrue(Blockly.utils.dom.hasClass(
+        labelField.textElement_, cssClass));
+  }
+  function assertDoesNotHaveClass(labelField, cssClass) {
+    labelField.fieldGroup_ = Blockly.utils.dom.createSvgElement('g', {}, null);
+    labelField.initView();
+    chai.assert.isFalse(Blockly.utils.dom.hasClass(
+        labelField.textElement_, cssClass));
+  }
   suite('Constructor', function() {
     test('Empty', function() {
       var labelField = new Blockly.FieldLabelSerializable();
@@ -167,4 +179,66 @@ suite('Label Serializable Fields', function() {
       });
     });
   });
+  suite('Customizations', function() {
+    test('JS Constructor', function() {
+      var field = new Blockly.FieldLabelSerializable('text', 'testClass');
+      assertHasClass(field, 'testClass');
+    });
+    test('JSON Definition', function() {
+      var field = Blockly.FieldLabelSerializable.fromJson({
+        class: 'testClass'
+      });
+      assertHasClass(field, 'testClass');
+    });
+    test('JS Configuration - Simple', function() {
+      var field = new Blockly.FieldLabelSerializable('text', null, {
+        class: 'testClass'
+      });
+      assertHasClass(field, 'testClass');
+    });
+    test('JS Configuration - Ignore', function() {
+      var field = new Blockly.FieldLabelSerializable('text', 'paramClass', {
+        class: 'configClass'
+      });
+      assertDoesNotHaveClass(field, 'paramClass');
+      assertHasClass(field, 'configClass');
+    });
+    test('JS Configuration - Ignore - \'\'', function() {
+      var field = new Blockly.FieldLabelSerializable('text', '', {
+        class: 'configClass'
+      });
+      assertHasClass(field, 'configClass');
+    });
+    test('JS Configuration - Ignore - Config \'\'', function() {
+      var field = new Blockly.FieldLabelSerializable('text', 'paramClass', {
+        class: ''
+      });
+      assertDoesNotHaveClass(field, 'paramClass');
+    });
+    suite('setClass', function() {
+      test('setClass', function() {
+        var field = new Blockly.FieldLabelSerializable();
+        field.fieldGroup_ = Blockly.utils.dom.createSvgElement('g', {}, null);
+        field.initView();
+        field.setClass('testClass');
+        // Don't call assertHasClass b/c we don't want to re-initialize.
+        chai.assert.isTrue(Blockly.utils.dom.hasClass(
+            field.textElement_, 'testClass'));
+      });
+      test('setClass Before Initialization', function() {
+        var field = new Blockly.FieldLabelSerializable();
+        field.setClass('testClass');
+        assertHasClass(field, 'testClass');
+      });
+      test('Remove Class', function() {
+        var field = new Blockly.FieldLabelSerializable('text', null, {
+          class: 'testClass'
+        });
+        assertHasClass(field, 'testClass');
+        field.setClass(null);
+        chai.assert.isFalse(Blockly.utils.dom.hasClass(
+            field.textElement_, 'testClass'));
+      });
+    });
+  });
 });
diff --git a/tests/mocha/field_label_test.js b/tests/mocha/field_label_test.js
index 8e6e53358..1ed552345 100644
--- a/tests/mocha/field_label_test.js
+++ b/tests/mocha/field_label_test.js
@@ -28,6 +28,18 @@ suite('Label Fields', function() {
   function assertValueDefault(labelField) {
     assertValue(labelField, '');
   }
+  function assertHasClass(labelField, cssClass) {
+    labelField.fieldGroup_ = Blockly.utils.dom.createSvgElement('g', {}, null);
+    labelField.initView();
+    chai.assert.isTrue(Blockly.utils.dom.hasClass(
+        labelField.textElement_, cssClass));
+  }
+  function assertDoesNotHaveClass(labelField, cssClass) {
+    labelField.fieldGroup_ = Blockly.utils.dom.createSvgElement('g', {}, null);
+    labelField.initView();
+    chai.assert.isFalse(Blockly.utils.dom.hasClass(
+        labelField.textElement_, cssClass));
+  }
   suite('Constructor', function() {
     test('Empty', function() {
       var labelField = new Blockly.FieldLabel();
@@ -156,4 +168,66 @@ suite('Label Fields', function() {
       });
     });
   });
+  suite('Customizations', function() {
+    test('JS Constructor', function() {
+      var field = new Blockly.FieldLabel('text', 'testClass');
+      assertHasClass(field, 'testClass');
+    });
+    test('JSON Definition', function() {
+      var field = Blockly.FieldLabel.fromJson({
+        class: 'testClass'
+      });
+      assertHasClass(field, 'testClass');
+    });
+    test('JS Configuration - Simple', function() {
+      var field = new Blockly.FieldLabel('text', null, {
+        class: 'testClass'
+      });
+      assertHasClass(field, 'testClass');
+    });
+    test('JS Configuration - Ignore', function() {
+      var field = new Blockly.FieldLabel('text', 'paramClass', {
+        class: 'configClass'
+      });
+      assertDoesNotHaveClass(field, 'paramClass');
+      assertHasClass(field, 'configClass');
+    });
+    test('JS Configuration - Ignore - \'\'', function() {
+      var field = new Blockly.FieldLabel('text', '', {
+        class: 'configClass'
+      });
+      assertHasClass(field, 'configClass');
+    });
+    test('JS Configuration - Ignore - Config \'\'', function() {
+      var field = new Blockly.FieldLabel('text', 'paramClass', {
+        class: ''
+      });
+      assertDoesNotHaveClass(field, 'paramClass');
+    });
+    suite('setClass', function() {
+      test('setClass', function() {
+        var field = new Blockly.FieldLabel();
+        field.fieldGroup_ = Blockly.utils.dom.createSvgElement('g', {}, null);
+        field.initView();
+        field.setClass('testClass');
+        // Don't call assertHasClass b/c we don't want to re-initialize.
+        chai.assert.isTrue(Blockly.utils.dom.hasClass(
+            field.textElement_, 'testClass'));
+      });
+      test('setClass Before Initialization', function() {
+        var field = new Blockly.FieldLabel();
+        field.setClass('testClass');
+        assertHasClass(field, 'testClass');
+      });
+      test('Remove Class', function() {
+        var field = new Blockly.FieldLabel('text', null, {
+          class: 'testClass'
+        });
+        assertHasClass(field, 'testClass');
+        field.setClass(null);
+        chai.assert.isFalse(Blockly.utils.dom.hasClass(
+            field.textElement_, 'testClass'));
+      });
+    });
+  });
 });