diff --git a/Gemfile b/Gemfile
index eb3e367894..2faf6002e5 100644
--- a/Gemfile
+++ b/Gemfile
@@ -79,7 +79,7 @@ gem 'actionpack-action_caching'
 # Once Rails is updated to 5.x we should bump directly to 0.10.x
 gem "active_model_serializers", "0.8.4"
 gem 'activerecord-session_store'
-gem 'acts-as-taggable-on', '~> 3.4'
+gem 'acts-as-taggable-on', '~> 4.0'
 gem 'angularjs-file-upload-rails', '~> 2.4.1'
 gem 'blockenspiel'
 gem 'custom_error_message', github: 'jeremydurham/custom-err-msg'
diff --git a/Gemfile.lock b/Gemfile.lock
index 02b4c3433b..63bb5e0f28 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -124,8 +124,8 @@ GEM
       multi_json (~> 1.3)
       thread_safe (~> 0.1)
       tzinfo (~> 0.3.37)
-    acts-as-taggable-on (3.5.0)
-      activerecord (>= 3.2, < 5)
+    acts-as-taggable-on (4.0.0)
+      activerecord (>= 4.0)
     acts_as_list (0.2.0)
       activerecord (>= 3.0)
     addressable (2.7.0)
@@ -697,7 +697,7 @@ DEPENDENCIES
   activerecord-import
   activerecord-postgresql-adapter
   activerecord-session_store
-  acts-as-taggable-on (~> 3.4)
+  acts-as-taggable-on (~> 4.0)
   acts_as_list (= 0.2.0)
   andand
   angular-rails-templates (~> 0.3.0)