diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 0827f31736..d276c536ac 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -19,6 +19,7 @@ jobs:
           - ruby3.1
           - ruby3.2
           - ruby3.3
+          - ruby3.4.0-preview1
         compiler:
           - gcc
           - clang
diff --git a/Rakefile b/Rakefile
index 5fad5a98fc..7c9c43a2b8 100644
--- a/Rakefile
+++ b/Rakefile
@@ -349,7 +349,7 @@ end
 
 def ruby_version_string
   string = ENV['RUBY'] || DEFAULT_HOST_RUBY_VERSION
-  raise 'must be in the format rubyX.Y' unless string =~ /^ruby\d\.\d$/
+  raise 'must be in the format rubyX.Y' unless string =~ /^ruby\d\.\d(?:\.\d-preview\d)?$/
   string
 end