diff --git a/Gemfile b/Gemfile
index 058f906a64f..31151be6faa 100644
--- a/Gemfile
+++ b/Gemfile
@@ -96,7 +96,7 @@ gem 'tzinfo-data', '~> 1.2023'
 gem 'webauthn', '~> 3.0'
 gem 'webpush', github: 'mastodon/webpush', ref: '9631ac63045cfabddacc69fc06e919b4c13eb913'
 
-gem 'json'
+gem 'json', '< 3'
 gem 'json-canonicalization', '~> 1.0'
 gem 'json-ld'
 gem 'json-ld-preloaded', '~> 3.2'
diff --git a/Gemfile.lock b/Gemfile.lock
index 199f34c23e2..88fe32a06e3 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -997,7 +997,7 @@ DEPENDENCIES
   ipaddr (~> 1.2)
   irb (~> 1.8)
   jd-paperclip-azure (~> 3.0)
-  json
+  json (< 3)
   json-canonicalization (~> 1.0)
   json-ld
   json-ld-preloaded (~> 3.2)