diff --git a/lib/6to5/file.js b/lib/6to5/file.js
index 93745c553f..05eab212f5 100644
--- a/lib/6to5/file.js
+++ b/lib/6to5/file.js
@@ -36,22 +36,12 @@ File.helpers = [
   "interop-require-wildcard",
   "typeof",
   "extends",
-  "get",
-  "observe-delete",
-  "observe-get",
-  "observe-update",
-  "observe-notify",
-  "observe-create"
+  "get"
 ];
 
 File.excludeHelpersFromRuntime = [
   "async-to-generator",
-  "typeof",
-  "observe-delete",
-  "observe-get",
-  "observe-update",
-  "observe-notify",
-  "observe-create"
+  "typeof"
 ];
 
 File.normaliseOptions = function (opts) {
diff --git a/lib/6to5/transformation/templates/observe-create.js b/lib/6to5/transformation/templates/observe-create.js
deleted file mode 100644
index 380d05459b..0000000000
--- a/lib/6to5/transformation/templates/observe-create.js
+++ /dev/null
@@ -1,4 +0,0 @@
-(function (obj, callback) {
-  global._6to5Obsevers = global._6to5Obsevers || [];
-  global._6to5Obsevers.push([obj, callback]);
-});
diff --git a/lib/6to5/transformation/templates/observe-delete.js b/lib/6to5/transformation/templates/observe-delete.js
deleted file mode 100644
index 8d0f4afe7c..0000000000
--- a/lib/6to5/transformation/templates/observe-delete.js
+++ /dev/null
@@ -1,3 +0,0 @@
-(function () {
-
-})
diff --git a/lib/6to5/transformation/templates/observe-get.js b/lib/6to5/transformation/templates/observe-get.js
deleted file mode 100644
index 8d0f4afe7c..0000000000
--- a/lib/6to5/transformation/templates/observe-get.js
+++ /dev/null
@@ -1,3 +0,0 @@
-(function () {
-
-})
diff --git a/lib/6to5/transformation/templates/observe-notify.js b/lib/6to5/transformation/templates/observe-notify.js
deleted file mode 100644
index 8d0f4afe7c..0000000000
--- a/lib/6to5/transformation/templates/observe-notify.js
+++ /dev/null
@@ -1,3 +0,0 @@
-(function () {
-
-})
diff --git a/lib/6to5/transformation/templates/observe-update.js b/lib/6to5/transformation/templates/observe-update.js
deleted file mode 100644
index 8d0f4afe7c..0000000000
--- a/lib/6to5/transformation/templates/observe-update.js
+++ /dev/null
@@ -1,3 +0,0 @@
-(function () {
-
-})
diff --git a/lib/6to5/transformation/transform.js b/lib/6to5/transformation/transform.js
index 4ce66d8203..6c118e03a9 100644
--- a/lib/6to5/transformation/transform.js
+++ b/lib/6to5/transformation/transform.js
@@ -80,7 +80,6 @@ _.each({
   generators:                require("./transformers/es6-generators"),
   restParameters:            require("./transformers/es6-rest-parameters"),
 
-  objectObserve:             require("./transformers/optional-object-observe"),
   protoToAssign:             require("./transformers/optional-proto-to-assign"),
 
   _declarations:             require("./transformers/_declarations"),
diff --git a/lib/6to5/transformation/transformers/optional-object-observe.js b/lib/6to5/transformation/transformers/optional-object-observe.js
deleted file mode 100644
index 4668b0bf8f..0000000000
--- a/lib/6to5/transformation/transformers/optional-object-observe.js
+++ /dev/null
@@ -1 +0,0 @@
-exports.optional = true;
diff --git a/test/fixtures/transformation/optional-object-observe/options.json b/test/fixtures/transformation/optional-object-observe/options.json
deleted file mode 100644
index 4ca12d931b..0000000000
--- a/test/fixtures/transformation/optional-object-observe/options.json
+++ /dev/null
@@ -1,3 +0,0 @@
-{
-  "optional": ["objectObserve"]
-}