diff --git a/core/names.js b/core/names.js
index bfe942ab9..6278c7dd2 100644
--- a/core/names.js
+++ b/core/names.js
@@ -26,6 +26,14 @@
 
 goog.provide('Blockly.Names');
 
+/**
+ * Constant to separate developer variable names from user-defined variable
+ * names when running generators.
+ * A developer variable will be declared as a global in the generated code, but
+ * will never be shown to the user in the workspace or stored in the variable
+ * map.
+ */
+Blockly.Names.DEVELOPER_VARIABLE_TYPE = 'DEVELOPER_VARIABLE';
 
 /**
  * Class for a database of entity names (variables, functions, etc).
@@ -62,6 +70,41 @@ Blockly.Names = function(reservedWords, opt_variablePrefix) {
 Blockly.Names.prototype.reset = function() {
   this.db_ = Object.create(null);
   this.dbReverse_ = Object.create(null);
+  this.variableMap_ = null;
+};
+
+/**
+ * Set the variable map that maps from variable name to variable object.
+ * @param {!Blockly.VariableMap} map The map to track.
+ * @package
+ */
+Blockly.Names.prototype.setVariableMap = function(map) {
+  this.variableMap_ = map;
+};
+
+/**
+ * Get the name for a user-defined variable, based on its ID.
+ * This should only be used for variables of type Blockly.Variables.NAME_TYPE.
+ * @param {string} id The ID to look up in the variable map.
+ * @return {?string} The name of the referenced variable, or null if there was
+ *     no variable map or the variable was not found in the map.
+ * @private
+ */
+Blockly.Names.prototype.getNameForUserVariable_ = function(id) {
+  if (!this.variableMap_) {
+    console.log('Deprecated call to Blockly.Names.prototype.getName without ' +
+        'defining a variable map. To fix, add the folowing code in your ' +
+        'generator\'s init() function:\n' +
+        'Blockly.YourGeneratorName.variableDB_.setVariableMap(' +
+        'workspace.getVariableMap());');
+    return null;
+  }
+  var variable = this.variableMap_.getVariableById(id);
+  if (variable) {
+    return variable.name;
+  } else {
+    return null;
+  }
 };
 
 /**
@@ -72,9 +115,18 @@ Blockly.Names.prototype.reset = function() {
  * @return {string} An entity name legal for the exported language.
  */
 Blockly.Names.prototype.getName = function(name, type) {
+  if (type == Blockly.Variables.NAME_TYPE) {
+    var varName = this.getNameForUserVariable_(name);
+    if (varName) {
+      name = varName;
+    }
+  }
   var normalized = name.toLowerCase() + '_' + type;
-  var prefix = (type == Blockly.Variables.NAME_TYPE) ?
-      this.variablePrefix_ : '';
+
+  var isVarType = type == Blockly.Variables.NAME_TYPE ||
+      type == Blockly.Names.DEVELOPER_VARIABLE_TYPE;
+
+  var prefix = isVarType ? this.variablePrefix_ : '';
   if (normalized in this.db_) {
     return prefix + this.db_[normalized];
   }
@@ -103,8 +155,9 @@ Blockly.Names.prototype.getDistinctName = function(name, type) {
   }
   safeName += i;
   this.dbReverse_[safeName] = true;
-  var prefix = (type == Blockly.Variables.NAME_TYPE) ?
-      this.variablePrefix_ : '';
+  var isVarType = type == Blockly.Variables.NAME_TYPE ||
+      type == Blockly.Names.DEVELOPER_VARIABLE_TYPE;
+  var prefix = isVarType ? this.variablePrefix_ : '';
   return prefix + safeName;
 };
 
diff --git a/core/variables.js b/core/variables.js
index b8d40028b..3eb3bcedf 100644
--- a/core/variables.js
+++ b/core/variables.js
@@ -100,6 +100,38 @@ Blockly.Variables.allVariables = function(root) {
   return root.getAllVariables();
 };
 
+/**
+ * Find all developer variables used by blocks in the workspace.
+ * Developer variables are never shown to the user, but are declared as global
+ * variables in the generated code.
+ * To declare developer variables, define the getDeveloperVariables function on
+ * your block and return a list of variable names.
+ * For use by generators.
+ * @param {!Blockly.Workspace} workspace The workspace to search.
+ * @return {!Array.<string>} A list of non-duplicated variable names.
+ * @package
+ */
+Blockly.Variables.allDeveloperVariables = function(workspace) {
+  var blocks = workspace.getAllBlocks();
+  var hash = {};
+  for (var i = 0; i < blocks.length; i++) {
+    var block = blocks[i];
+    if (block.getDeveloperVars) {
+      var devVars = block.getDeveloperVars();
+      for (var j = 0; j < devVars.length; j++) {
+        hash[devVars[j]] = devVars[j];
+      }
+    }
+  }
+
+  // Flatten the hash into a list.
+  var list = [];
+  for (var name in hash) {
+    list.push(hash[name]);
+  }
+  return list;
+};
+
 /**
  * Construct the elements (blocks and button) required by the flyout for the
  * variable category.
diff --git a/generators/dart.js b/generators/dart.js
index 83ef76cd6..1d3c93b75 100644
--- a/generators/dart.js
+++ b/generators/dart.js
@@ -102,13 +102,25 @@ Blockly.Dart.init = function(workspace) {
     Blockly.Dart.variableDB_.reset();
   }
 
+  Blockly.Dart.variableDB_.setVariableMap(workspace.getVariableMap());
+
   var defvars = [];
+  // Add user variables.
   var variables = workspace.getAllVariables();
-  if (variables.length) {
-    for (var i = 0; i < variables.length; i++) {
-      defvars[i] = Blockly.Dart.variableDB_.getName(variables[i].name,
-          Blockly.Variables.NAME_TYPE);
-    }
+  for (var i = 0; i < variables.length; i++) {
+    defvars[i] = Blockly.Dart.variableDB_.getName(variables[i].name,
+        Blockly.Variables.NAME_TYPE);
+  }
+
+  // Add developer variables (not created or named by the user).
+  var devVarList = Blockly.Variables.allDeveloperVariables(workspace);
+  for (var i = 0; i < devVarList.length; i++) {
+    defvars.push(Blockly.Dart.variableDB_.getName(devVarList[i],
+        Blockly.Names.DEVELOPER_VARIABLE_TYPE));
+  }
+
+  // Declare all of the variables.
+  if (defvars.length) {
     Blockly.Dart.definitions_['variables'] =
         'var ' + defvars.join(', ') + ';';
   }
diff --git a/generators/javascript.js b/generators/javascript.js
index 00b96bcc1..864ae50c3 100644
--- a/generators/javascript.js
+++ b/generators/javascript.js
@@ -152,13 +152,25 @@ Blockly.JavaScript.init = function(workspace) {
     Blockly.JavaScript.variableDB_.reset();
   }
 
+  Blockly.JavaScript.variableDB_.setVariableMap(workspace.getVariableMap());
+
   var defvars = [];
+  // Add user variables.
   var variables = workspace.getAllVariables();
-  if (variables.length) {
-    for (var i = 0; i < variables.length; i++) {
-      defvars[i] = Blockly.JavaScript.variableDB_.getName(variables[i].name,
-          Blockly.Variables.NAME_TYPE);
-    }
+  for (var i = 0; i < variables.length; i++) {
+    defvars[i] = Blockly.JavaScript.variableDB_.getName(variables[i].name,
+        Blockly.Variables.NAME_TYPE);
+  }
+
+  // Add developer variables (not created or named by the user).
+  var devVarList = Blockly.Variables.allDeveloperVariables(workspace);
+  for (var i = 0; i < devVarList.length; i++) {
+    defvars.push(Blockly.JavaScript.variableDB_.getName(devVarList[i],
+        Blockly.Names.DEVELOPER_VARIABLE_TYPE));
+  }
+
+  // Declare all of the variables.
+  if (defvars.length) {
     Blockly.JavaScript.definitions_['variables'] =
         'var ' + defvars.join(', ') + ';';
   }
diff --git a/generators/lua.js b/generators/lua.js
index 1118a31e4..b7f8d5c90 100644
--- a/generators/lua.js
+++ b/generators/lua.js
@@ -109,6 +109,7 @@ Blockly.Lua.init = function(workspace) {
   } else {
     Blockly.Lua.variableDB_.reset();
   }
+  Blockly.Lua.variableDB_.setVariableMap(workspace.getVariableMap());
 };
 
 /**
diff --git a/generators/php.js b/generators/php.js
index 2c65a6809..6dc81ba62 100644
--- a/generators/php.js
+++ b/generators/php.js
@@ -149,14 +149,25 @@ Blockly.PHP.init = function(workspace) {
     Blockly.PHP.variableDB_.reset();
   }
 
+  Blockly.PHP.variableDB_.setVariableMap(workspace.getVariableMap());
+
   var defvars = [];
   var varName;
-  var variables = Blockly.Variables.allVariables(workspace);
+  var variables = workspace.getAllVariables();
   for (var i = 0, variable; variable = variables[i]; i++) {
     varName = variable.name;
     defvars[i] = Blockly.PHP.variableDB_.getName(varName,
         Blockly.Variables.NAME_TYPE) + ';';
   }
+
+  // Add developer variables (not created or named by the user).
+  var devVarList = Blockly.Variables.allDeveloperVariables(workspace);
+  for (var i = 0; i < devVarList.length; i++) {
+    defvars.push(Blockly.PHP.variableDB_.getName(devVarList[i],
+        Blockly.Names.DEVELOPER_VARIABLE_TYPE) + ';');
+  }
+
+  // Declare all of the variables.
   Blockly.PHP.definitions_['variables'] = defvars.join('\n');
 };
 
diff --git a/generators/python.js b/generators/python.js
index e81a04234..ab927d13b 100644
--- a/generators/python.js
+++ b/generators/python.js
@@ -160,12 +160,21 @@ Blockly.Python.init = function(workspace) {
     Blockly.Python.variableDB_.reset();
   }
 
+  Blockly.Python.variableDB_.setVariableMap(workspace.getVariableMap());
+
   var defvars = [];
   var variables = workspace.getAllVariables();
   for (var i = 0; i < variables.length; i++) {
     defvars[i] = Blockly.Python.variableDB_.getName(variables[i].name,
         Blockly.Variables.NAME_TYPE) + ' = None';
   }
+
+  // Add developer variables (not created or named by the user).
+  var devVarList = Blockly.Variables.allDeveloperVariables(workspace);
+  for (var i = 0; i < devVarList.length; i++) {
+    defvars.push(Blockly.Python.variableDB_.getName(devVarList[i],
+        Blockly.Names.DEVELOPER_VARIABLE_TYPE) + ' = None');
+  }
   Blockly.Python.definitions_['variables'] = defvars.join('\n');
 };
 
diff --git a/tests/generators/unittest.js b/tests/generators/unittest.js
index 5c471d1b7..6b7378210 100644
--- a/tests/generators/unittest.js
+++ b/tests/generators/unittest.js
@@ -34,7 +34,7 @@ Blockly.Blocks['unittest_main'] = {
     this.setTooltip('Executes the enclosed unit tests,\n' +
                     'then prints a summary.');
   },
-  getVars: function() {
+  getDeveloperVars: function() {
     return ['unittestResults'];
   }
 };
@@ -54,7 +54,7 @@ Blockly.Blocks['unittest_assertequals'] = {
         .appendField('expected');
     this.setTooltip('Tests that "actual == expected".');
   },
-  getVars: function() {
+  getDeveloperVars: function() {
     return ['unittestResults'];
   }
 };
@@ -74,7 +74,7 @@ Blockly.Blocks['unittest_assertvalue'] = {
         [['true', 'TRUE'], ['false', 'FALSE'], ['null', 'NULL']]), 'EXPECTED');
     this.setTooltip('Tests that the value is true, false, or null.');
   },
-  getVars: function() {
+  getDeveloperVars: function() {
     return ['unittestResults'];
   }
 };
@@ -90,7 +90,7 @@ Blockly.Blocks['unittest_fail'] = {
         .appendField('fail');
     this.setTooltip('Records an error.');
   },
-  getVars: function() {
+  getDeveloperVars: function() {
     return ['unittestResults'];
   }
 };
diff --git a/tests/generators/unittest_dart.js b/tests/generators/unittest_dart.js
index 97e6ae466..436bcff63 100644
--- a/tests/generators/unittest_dart.js
+++ b/tests/generators/unittest_dart.js
@@ -27,7 +27,7 @@
 Blockly.Dart['unittest_main'] = function(block) {
   // Container for unit tests.
   var resultsVar = Blockly.Dart.variableDB_.getName('unittestResults',
-      Blockly.Variables.NAME_TYPE);
+      Blockly.Names.DEVELOPER_VARIABLE_TYPE);
   var functionName = Blockly.Dart.provideFunction_(
       'unittest_report',
       [ 'String ' + Blockly.Dart.FUNCTION_NAME_PLACEHOLDER_ + '() {',
@@ -71,7 +71,7 @@ Blockly.Dart['unittest_main'] = function(block) {
 
 Blockly.Dart['unittest_main'].defineAssert_ = function() {
   var resultsVar = Blockly.Dart.variableDB_.getName('unittestResults',
-      Blockly.Variables.NAME_TYPE);
+      Blockly.Names.DEVELOPER_VARIABLE_TYPE);
   var functionName = Blockly.Dart.provideFunction_(
       'unittest_assertequals',
       [ 'void ' + Blockly.Dart.FUNCTION_NAME_PLACEHOLDER_ +
@@ -139,7 +139,7 @@ Blockly.Dart['unittest_assertvalue'] = function(block) {
 Blockly.Dart['unittest_fail'] = function(block) {
   // Always assert an error.
   var resultsVar = Blockly.Dart.variableDB_.getName('unittestResults',
-      Blockly.Variables.NAME_TYPE);
+      Blockly.Names.DEVELOPER_VARIABLE_TYPE);
   var message = Blockly.Dart.quote_(block.getFieldValue('MESSAGE'));
   var functionName = Blockly.Dart.provideFunction_(
       'unittest_fail',
diff --git a/tests/generators/unittest_javascript.js b/tests/generators/unittest_javascript.js
index 9fda5be30..92d8a2913 100644
--- a/tests/generators/unittest_javascript.js
+++ b/tests/generators/unittest_javascript.js
@@ -27,7 +27,7 @@
 Blockly.JavaScript['unittest_main'] = function(block) {
   // Container for unit tests.
   var resultsVar = Blockly.JavaScript.variableDB_.getName('unittestResults',
-      Blockly.Variables.NAME_TYPE);
+      Blockly.Names.DEVELOPER_VARIABLE_TYPE);
   var functionName = Blockly.JavaScript.provideFunction_(
       'unittest_report',
       [ 'function ' + Blockly.JavaScript.FUNCTION_NAME_PLACEHOLDER_ + '() {',
@@ -72,7 +72,7 @@ Blockly.JavaScript['unittest_main'] = function(block) {
 
 Blockly.JavaScript['unittest_main'].defineAssert_ = function(block) {
   var resultsVar = Blockly.JavaScript.variableDB_.getName('unittestResults',
-      Blockly.Variables.NAME_TYPE);
+      Blockly.Names.DEVELOPER_VARIABLE_TYPE);
   var functionName = Blockly.JavaScript.provideFunction_(
       'assertEquals',
       [ 'function ' + Blockly.JavaScript.FUNCTION_NAME_PLACEHOLDER_ +
@@ -143,7 +143,7 @@ Blockly.JavaScript['unittest_assertvalue'] = function(block) {
 Blockly.JavaScript['unittest_fail'] = function(block) {
   // Always assert an error.
   var resultsVar = Blockly.JavaScript.variableDB_.getName('unittestResults',
-      Blockly.Variables.NAME_TYPE);
+      Blockly.Names.DEVELOPER_VARIABLE_TYPE);
   var message = Blockly.JavaScript.quote_(block.getFieldValue('MESSAGE'));
   var functionName = Blockly.JavaScript.provideFunction_(
       'unittest_fail',
diff --git a/tests/generators/unittest_lua.js b/tests/generators/unittest_lua.js
index 73c5dbe0d..2a9015c10 100644
--- a/tests/generators/unittest_lua.js
+++ b/tests/generators/unittest_lua.js
@@ -27,7 +27,7 @@
 Blockly.Lua['unittest_main'] = function(block) {
   // Container for unit tests.
   var resultsVar = Blockly.Lua.variableDB_.getName('unittestResults',
-      Blockly.Variables.NAME_TYPE);
+      Blockly.Names.DEVELOPER_VARIABLE_TYPE);
   var functionName = Blockly.Lua.provideFunction_(
       'unittest_report',
       ['function ' + Blockly.Lua.FUNCTION_NAME_PLACEHOLDER_ + '()',
@@ -70,7 +70,7 @@ Blockly.Lua['unittest_main'] = function(block) {
 
 Blockly.Lua['unittest_main'].defineAssert_ = function(block) {
   var resultsVar = Blockly.Lua.variableDB_.getName('unittestResults',
-      Blockly.Variables.NAME_TYPE);
+      Blockly.Names.DEVELOPER_VARIABLE_TYPE);
   var functionName = Blockly.Lua.provideFunction_(
       'assertEquals',
       ['function ' + Blockly.Lua.FUNCTION_NAME_PLACEHOLDER_ +
@@ -149,7 +149,7 @@ Blockly.Lua['unittest_assertvalue'] = function(block) {
 Blockly.Lua['unittest_fail'] = function(block) {
   // Always assert an error.
   var resultsVar = Blockly.Lua.variableDB_.getName('unittestResults',
-      Blockly.Variables.NAME_TYPE);
+      Blockly.Names.DEVELOPER_VARIABLE_TYPE);
   var message = Blockly.Lua.quote_(block.getFieldValue('MESSAGE'));
   var functionName = Blockly.Lua.provideFunction_(
       'unittest_fail',
diff --git a/tests/generators/unittest_php.js b/tests/generators/unittest_php.js
index 528e5971d..54d7e4e97 100644
--- a/tests/generators/unittest_php.js
+++ b/tests/generators/unittest_php.js
@@ -27,7 +27,7 @@
 Blockly.PHP['unittest_main'] = function(block) {
   // Container for unit tests.
   var resultsVar = Blockly.PHP.variableDB_.getName('unittestResults',
-      Blockly.Variables.NAME_TYPE);
+      Blockly.Names.DEVELOPER_VARIABLE_TYPE);
   var functionName = Blockly.PHP.provideFunction_(
       'unittest_report',
       [ 'function ' + Blockly.PHP.FUNCTION_NAME_PLACEHOLDER_ + '() {',
@@ -72,7 +72,7 @@ Blockly.PHP['unittest_main'] = function(block) {
 
 Blockly.PHP['unittest_main'].defineAssert_ = function(block) {
   var resultsVar = Blockly.PHP.variableDB_.getName('unittestResults',
-      Blockly.Variables.NAME_TYPE);
+      Blockly.Names.DEVELOPER_VARIABLE_TYPE);
   var functionName = Blockly.PHP.provideFunction_(
       'assertEquals',
       ['function ' + Blockly.PHP.FUNCTION_NAME_PLACEHOLDER_ +
@@ -129,7 +129,7 @@ Blockly.PHP['unittest_assertvalue'] = function(block) {
 Blockly.PHP['unittest_fail'] = function(block) {
   // Always assert an error.
   var resultsVar = Blockly.PHP.variableDB_.getName('unittestResults',
-      Blockly.Variables.NAME_TYPE);
+      Blockly.Names.DEVELOPER_VARIABLE_TYPE);
   var message = Blockly.PHP.quote_(block.getFieldValue('MESSAGE'));
   var functionName = Blockly.PHP.provideFunction_(
       'unittest_fail',
diff --git a/tests/generators/unittest_python.js b/tests/generators/unittest_python.js
index 5e00e26be..91fabd179 100644
--- a/tests/generators/unittest_python.js
+++ b/tests/generators/unittest_python.js
@@ -27,7 +27,7 @@
 Blockly.Python['unittest_main'] = function(block) {
   // Container for unit tests.
   var resultsVar = Blockly.Python.variableDB_.getName('unittestResults',
-      Blockly.Variables.NAME_TYPE);
+      Blockly.Names.DEVELOPER_VARIABLE_TYPE);
   var functionName = Blockly.Python.provideFunction_(
       'unittest_report',
       ['def ' + Blockly.Python.FUNCTION_NAME_PLACEHOLDER_ + '():',
@@ -68,7 +68,7 @@ Blockly.Python['unittest_main'] = function(block) {
 
 Blockly.Python['unittest_main'].defineAssert_ = function() {
   var resultsVar = Blockly.Python.variableDB_.getName('unittestResults',
-      Blockly.Variables.NAME_TYPE);
+      Blockly.Names.DEVELOPER_VARIABLE_TYPE);
   var functionName = Blockly.Python.provideFunction_(
       'assertEquals',
       ['def ' + Blockly.Python.FUNCTION_NAME_PLACEHOLDER_ +
@@ -117,7 +117,7 @@ Blockly.Python['unittest_assertvalue'] = function(block) {
 Blockly.Python['unittest_fail'] = function(block) {
   // Always assert an error.
   var resultsVar = Blockly.Python.variableDB_.getName('unittestResults',
-      Blockly.Variables.NAME_TYPE);
+      Blockly.Names.DEVELOPER_VARIABLE_TYPE);
   var message = Blockly.Python.quote_(block.getFieldValue('MESSAGE'));
   var functionName = Blockly.Python.provideFunction_(
       'fail',