diff --git a/Appraisals b/Appraisals
index 303c1cc76..6933820c8 100644
--- a/Appraisals
+++ b/Appraisals
@@ -2,6 +2,8 @@
 
 appraise "rails-7-1" do
   gem "railties", "~> 7.1.0"
+  # json 3 rejects the quirks_mode option this Active Support passes.
+  gem "json", "< 3"
 end
 
 appraise "rails-7-2" do
@@ -10,6 +12,8 @@ end
 
 appraise "rails-8-0" do
   gem "railties", "~> 8.0.0"
+  # json 3 rejects the quirks_mode option this Active Support passes.
+  gem "json", "< 3"
 end
 
 appraise "rails-8-1" do
diff --git a/gemfiles/rails_7_1.gemfile b/gemfiles/rails_7_1.gemfile
index 036d98368..5fd12a49c 100644
--- a/gemfiles/rails_7_1.gemfile
+++ b/gemfiles/rails_7_1.gemfile
@@ -3,5 +3,6 @@
 source "https://rubygems.org"
 
 gem "railties", "~> 7.1.0"
+gem "json", "< 3"
 
 gemspec path: "../"
diff --git a/gemfiles/rails_8_0.gemfile b/gemfiles/rails_8_0.gemfile
index 28bd9f00e..297d3f85c 100644
--- a/gemfiles/rails_8_0.gemfile
+++ b/gemfiles/rails_8_0.gemfile
@@ -3,5 +3,6 @@
 source "https://rubygems.org"
 
 gem "railties", "~> 8.0.0"
+gem "json", "< 3"
 
 gemspec path: "../"