diff --git a/CHANGELOG.md b/CHANGELOG.md
index c4579b2b1..fd7adaf04 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,8 @@
     determining VirtualBox version. [GH-658]
   - Debian/Ubuntu uses `ifdown` again, instead of `ifconfig xxx down`, since
     the behavior seems different/wrong.
+  - Give a nice error if `:vagrant` is used as a JSON key, since Vagrant
+    uses this. [GH-661]
 
 ## 0.9.1 (January 18, 2012)
 
diff --git a/lib/vagrant/provisioners/chef.rb b/lib/vagrant/provisioners/chef.rb
index 933505cf1..2df2d4f09 100644
--- a/lib/vagrant/provisioners/chef.rb
+++ b/lib/vagrant/provisioners/chef.rb
@@ -147,6 +147,12 @@ module Vagrant
           run_list << name
         end
 
+        def validate(env, errors)
+          super
+
+          errors.add(I18n.t("vagrant.config.chef.vagrant_as_json_key")) if @json.has_key?(:vagrant)
+        end
+
         def instance_variables_hash
           # Overridden so that the 'json' key could be removed, since its just
           # merged into the config anyways
diff --git a/templates/locales/en.yml b/templates/locales/en.yml
index cac2cb01c..331493914 100644
--- a/templates/locales/en.yml
+++ b/templates/locales/en.yml
@@ -188,9 +188,11 @@ en:
       common:
         error_empty: "`%{field}` must be filled in."
       chef:
-        run_list_empty: "Run list must not be empty."
         cookbooks_path_empty: "Must specify a cookbooks path for chef solo."
+        run_list_empty: "Run list must not be empty."
         server_url_empty: "Chef server URL must be populated."
+        vagrant_as_json_key: |-
+          `vagrant` cannot be a JSON key, because it is used by Vagrant already.
         validation_key_path: "Validation key path must be valid path to your chef server validation key."
       ssh:
         private_key_missing: "`private_key_path` file must exist: %{path}"