diff --git a/enterprise/app/services/captain/audience_matcher.rb b/enterprise/app/services/captain/audience_matcher.rb
index ba707e179..a78eb8fc7 100644
--- a/enterprise/app/services/captain/audience_matcher.rb
+++ b/enterprise/app/services/captain/audience_matcher.rb
@@ -72,11 +72,17 @@ class Captain::AudienceMatcher
   # ignore the "+" prefix, and text compares case-insensitively.
   def value_equal?(key, actual, expected)
     return Array(actual).include?(expected) if key == 'labels'
-    return ActiveModel::Type::Boolean.new.cast(expected) == actual if [true, false].include?(actual)
+    return ActiveModel::Type::Boolean.new.cast(expected) == (actual == true) if boolean_condition?(actual, expected)
 
     normalize(key, actual) == normalize(key, expected)
   end
 
+  # An unset checkbox attribute counts as false; the expected value identifies
+  # the condition as boolean when the attribute is missing.
+  def boolean_condition?(actual, expected)
+    [true, false].include?(actual) || (actual.nil? && %w[true false].include?(expected.to_s))
+  end
+
   def normalize(key, value)
     return value if value.nil?
     return "+#{value.to_s.delete('+')}" if key == 'phone_number'
diff --git a/spec/enterprise/services/captain/audience_matcher_spec.rb b/spec/enterprise/services/captain/audience_matcher_spec.rb
index 2a6604007..0c1db8032 100644
--- a/spec/enterprise/services/captain/audience_matcher_spec.rb
+++ b/spec/enterprise/services/captain/audience_matcher_spec.rb
@@ -37,6 +37,18 @@ RSpec.describe Captain::AudienceMatcher do
         expect(matches?(leaf('plan_tier', 'not_equal_to', 'free'))).to be(true)
       end
 
+      it 'matches checkbox custom attributes' do
+        contact.update!(custom_attributes: contact.custom_attributes.merge('newsletter_opt_in' => true))
+        expect(matches?(leaf('newsletter_opt_in', 'equal_to', 'true'))).to be(true)
+        expect(matches?(leaf('newsletter_opt_in', 'equal_to', 'false'))).to be(false)
+      end
+
+      it 'treats a missing checkbox attribute as false' do
+        expect(matches?(leaf('newsletter_opt_in', 'equal_to', 'false'))).to be(true)
+        expect(matches?(leaf('newsletter_opt_in', 'equal_to', 'true'))).to be(false)
+        expect(matches?(leaf('newsletter_opt_in', 'not_equal_to', 'true'))).to be(true)
+      end
+
       it 'supports contains / starts_with on text' do
         expect(matches?(leaf('email', 'contains', contact.email[2..5]))).to be(true)
         expect(matches?(leaf('city', 'starts_with', 'Bos'))).to be(true)