diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index b62e8dc..de10ef6 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -11,6 +11,7 @@ jobs:
       matrix:
         ruby-version:
           - head
+          - '3.3'
           - '3.2'
           - '3.1'
           - '3.0'
@@ -20,7 +21,7 @@ jobs:
           - '2.4'
           - '2.3'
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: Set up Ruby ${{ matrix.ruby-version }}
       uses: ruby/setup-ruby@v1
       with:
diff --git a/lib/formulaic/form.rb b/lib/formulaic/form.rb
index 06534c9..404dfd9 100644
--- a/lib/formulaic/form.rb
+++ b/lib/formulaic/form.rb
@@ -1,3 +1,4 @@
+require 'active_support'
 require 'active_support/time_with_zone'
 
 module Formulaic
diff --git a/lib/formulaic/label.rb b/lib/formulaic/label.rb
index 0ebf5ab..501efa2 100644
--- a/lib/formulaic/label.rb
+++ b/lib/formulaic/label.rb
@@ -1,3 +1,6 @@
+require 'active_support'
+require 'active_support/core_ext/object/blank'
+
 module Formulaic
   class Label
     attr_reader :model_name, :attribute, :action