diff --git a/lib/6to5/transformers/constants.js b/lib/6to5/transformers/constants.js
index 6df3a4dbfe..6257b8a985 100644
--- a/lib/6to5/transformers/constants.js
+++ b/lib/6to5/transformers/constants.js
@@ -55,7 +55,9 @@ exports.ForStatement = function (node) {
   traverse(node, function (child) {
     if (child._ignoreConstant) return;
 
-    if (child.type === "VariableDeclarator") {
+    if (child.type === "VariableDeclarator" ||
+        child.type === "FunctionDeclaration" ||
+        child.type === "ClassDeclaration") {
       check(child, child.id.name);
     } else if (child.type === "AssignmentExpression") {
       check(child, child.left.name);
diff --git a/test/fixtures/syntax/constants/no-classes/actual.js b/test/fixtures/syntax/constants/no-classes/actual.js
new file mode 100644
index 0000000000..4d0266bd50
--- /dev/null
+++ b/test/fixtures/syntax/constants/no-classes/actual.js
@@ -0,0 +1,5 @@
+const MULTIPLIER = 5;
+
+class MULTIPLIER {
+
+}
diff --git a/test/fixtures/syntax/constants/no-classes/options.json b/test/fixtures/syntax/constants/no-classes/options.json
new file mode 100644
index 0000000000..9b96d41ac9
--- /dev/null
+++ b/test/fixtures/syntax/constants/no-classes/options.json
@@ -0,0 +1,3 @@
+{
+  "throws": "MULTIPLIER is read-only"
+}
diff --git a/test/fixtures/syntax/constants/no-functions/actual.js b/test/fixtures/syntax/constants/no-functions/actual.js
new file mode 100644
index 0000000000..8b3451172f
--- /dev/null
+++ b/test/fixtures/syntax/constants/no-functions/actual.js
@@ -0,0 +1,5 @@
+const MULTIPLIER = 5;
+
+function MULTIPLIER() {
+
+}
diff --git a/test/fixtures/syntax/constants/no-functions/options.json b/test/fixtures/syntax/constants/no-functions/options.json
new file mode 100644
index 0000000000..9b96d41ac9
--- /dev/null
+++ b/test/fixtures/syntax/constants/no-functions/options.json
@@ -0,0 +1,3 @@
+{
+  "throws": "MULTIPLIER is read-only"
+}