diff --git a/actionpack/lib/action_dispatch/http/mime_types.rb b/actionpack/lib/action_dispatch/http/mime_types.rb
index 8356d1a238aa1..de7c181ff04aa 100644
--- a/actionpack/lib/action_dispatch/http/mime_types.rb
+++ b/actionpack/lib/action_dispatch/http/mime_types.rb
@@ -28,7 +28,7 @@
 
 # http://www.ietf.org/rfc/rfc4627.txt
 # http://www.json.org/JSONRequest.html
-Mime::Type.register "application/json", :json, %w( text/x-json application/jsonrequest application/vnd.api+json )
+Mime::Type.register "application/json", :json, %w( text/x-json application/jsonrequest )
 
 Mime::Type.register "application/pdf", :pdf, [], %w(pdf)
 Mime::Type.register "application/zip", :zip, [], %w(zip)
diff --git a/actionpack/test/dispatch/request/json_params_parsing_test.rb b/actionpack/test/dispatch/request/json_params_parsing_test.rb
index a3992ad00835a..71ad31ee15576 100644
--- a/actionpack/test/dispatch/request/json_params_parsing_test.rb
+++ b/actionpack/test/dispatch/request/json_params_parsing_test.rb
@@ -37,9 +37,9 @@ def teardown
     )
   end
 
-  test "parses json params for application/vnd.api+json" do
+  test "does not parses unregistered media types such as application/vnd.api+json" do
     assert_parses(
-      {"person" => {"name" => "David"}},
+      {},
       "{\"person\": {\"name\": \"David\"}}", { 'CONTENT_TYPE' => 'application/vnd.api+json' }
     )
   end
@@ -143,13 +143,6 @@ def teardown
     )
   end
 
-  test "parses json params for application/vnd.api+json" do
-    assert_parses(
-      {"user" => {"username" => "sikachu"}, "username" => "sikachu"},
-      "{\"username\": \"sikachu\"}", { 'CONTENT_TYPE' => 'application/vnd.api+json' }
-    )
-  end
-
   test "parses json with non-object JSON content" do
     assert_parses(
       {"user" => {"_json" => "string content" }, "_json" => "string content" },