diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index cb0f483..ac8ffcd 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -20,6 +20,7 @@ jobs:
           - '3.0'
           - '3.1'
           - '3.2'
+          - '3.3'
           - 'head'
         exclude:
           - ruby: '2.3'
diff --git a/CHANGELOG.md b/CHANGELOG.md
index f4afa00..fe023ce 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,7 @@
+## Unreleased
+
+ - CI: Add Ruby 3.3 to build matrix. (https://github.com/zombocom/rack-timeout/pull/217)
+
 ## 0.7.0
 
  - Honor an `X-Request-Start` header with the `t=<microseconds>` format, to allow using `wait_timeout` functionality with Apache (https://github.com/zombocom/rack-timeout/pull/210)