diff --git a/test/Dockerfile.distro b/test/Dockerfile.distro
index 21c1840727..c7fb0ba964 100644
--- a/test/Dockerfile.distro
+++ b/test/Dockerfile.distro
@@ -215,7 +215,7 @@ RUN install-tool uv 0.9.17
 FROM build AS test-ruby
 
 # renovate: datasource=github-releases packageName=containerbase/ruby-prebuild versioning=ruby
-RUN install-tool ruby 3.4.8
+RUN install-tool ruby 4.0.0
 # renovate: datasource=rubygems versioning=ruby
 RUN install-tool bundler 2.7.2
 # renovate: datasource=rubygems versioning=ruby
diff --git a/test/ruby/Dockerfile b/test/ruby/Dockerfile
index 1c6c38b679..be51f42764 100644
--- a/test/ruby/Dockerfile
+++ b/test/ruby/Dockerfile
@@ -44,7 +44,7 @@ WORKDIR /test
 FROM base AS build
 
 # renovate: datasource=github-releases packageName=containerbase/ruby-prebuild versioning=ruby
-RUN install-tool ruby 3.4.8
+RUN install-tool ruby 4.0.0
 
 #--------------------------------------
 # test: global bundler
diff --git a/test/ruby/Dockerfile.arm64 b/test/ruby/Dockerfile.arm64
index d3337700fc..d3d8154639 100644
--- a/test/ruby/Dockerfile.arm64
+++ b/test/ruby/Dockerfile.arm64
@@ -38,7 +38,7 @@ ARG CONTAINERBASE_LOG_LEVEL
 FROM base AS test-ruby
 
 # renovate: datasource=github-releases packageName=containerbase/ruby-prebuild versioning=ruby
-RUN install-tool ruby 3.4.8
+RUN install-tool ruby 4.0.0
 
 #--------------------------------------
 # Image: bundler