diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 3398ef641..475e2d957 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -15,7 +15,8 @@ jobs:
       fail-fast: false
       matrix:
         ruby:
-          - 2.7
+          - '2.7'
+          - '3.0'
         db:
           - mysql
           - postgresql
diff --git a/.ruby-version b/.ruby-version
index 1effb0034..9f55b2ccb 100644
--- a/.ruby-version
+++ b/.ruby-version
@@ -1 +1 @@
-2.7
+3.0
diff --git a/docker/develop/Dockerfile b/docker/develop/Dockerfile
index 44182f765..6a0e93cda 100644
--- a/docker/develop/Dockerfile
+++ b/docker/develop/Dockerfile
@@ -1,4 +1,4 @@
-FROM docker.io/amd64/ruby:2.7-slim-bullseye
+FROM docker.io/amd64/ruby:3.0-slim-bullseye
 
 RUN DEBIAN_FRONTEND=noninteractive \
     apt-get update && \