diff --git a/buildpacks/ruby/CHANGELOG.md b/buildpacks/ruby/CHANGELOG.md
index 20eefd7..3fb1c48 100644
--- a/buildpacks/ruby/CHANGELOG.md
+++ b/buildpacks/ruby/CHANGELOG.md
@@ -9,6 +9,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Fixed
 
+- Ruby pre-release verssions like `3.4.0.rc1` now work as expected. ([#372](https://github.com/heroku/buildpacks-ruby/pull/372))
 - Layer metadata deserialization to Rust structs is now using `#[serde(deny_unknown_fields)]` this prevents the accidental scenario where metadata containing a superset of fields could accidentally be deserialized to the wrong struct. It's unlikely this is currently happening with the current buildpack, but it's a possibly-observable difference so it's being listed ([#371](https://github.com/heroku/buildpacks-ruby/pull/371))
 
 ## [4.0.1] - 2024-12-11
diff --git a/commons/src/gemfile_lock.rs b/commons/src/gemfile_lock.rs
index 455222d..fd91fc4 100644
--- a/commons/src/gemfile_lock.rs
+++ b/commons/src/gemfile_lock.rs
@@ -116,12 +116,12 @@ impl FromStr for GemfileLock {
     type Err = std::convert::Infallible;
 
     fn from_str(string: &str) -> Result<Self, Self::Err> {
-        let bundled_with_re = Regex::new("BUNDLED WITH\\s   (\\d+\\.\\d+\\.\\d+)")
-            .expect("Internal error: Bad regex"); // Checked via clippy
-        let main_ruby_version_re = Regex::new("RUBY VERSION\\s   ruby (\\d+\\.\\d+\\.\\d+)")
-            .expect("Internal error: Bad regex"); // Checked via clippy
-        let jruby_version_re =
-            Regex::new("\\(jruby ((\\d+|\\.)+)\\)").expect("Internal error: Bad regex"); // Checked via clippy
+        let bundled_with_re =
+            Regex::new("BUNDLED WITH\\s   (\\d+\\.\\d+\\.\\d+)").expect("Clippy checked");
+        let main_ruby_version_re =
+            Regex::new("RUBY VERSION\\s   ruby (\\d+\\.\\d+\\.\\d+((-|\\.)\\S*\\d+)?)")
+                .expect("Clippy checked");
+        let jruby_version_re = Regex::new("\\(jruby ((\\d+|\\.)+)\\)").expect("Clippy checked");
 
         let bundler_version = match bundled_with_re.captures(string).and_then(|c| c.get(1)) {
             Some(result) => BundlerVersion::Explicit(result.as_str().to_string()),
@@ -152,6 +152,75 @@ impl FromStr for GemfileLock {
 mod tests {
     use super::*;
 
+    #[test]
+    fn test_does_not_capture_patch_version() {
+        let info = GemfileLock::from_str(
+            r"
+RUBY VERSION
+   ruby 3.3.5p100
+
+BUNDLED WITH
+   2.3.4
+",
+        )
+        .unwrap();
+
+        assert_eq!(
+            info.bundler_version,
+            BundlerVersion::Explicit("2.3.4".to_string())
+        );
+        assert_eq!(
+            info.ruby_version,
+            RubyVersion::Explicit("3.3.5".to_string())
+        );
+    }
+
+    #[test]
+    fn test_rc_dot_version() {
+        let info = GemfileLock::from_str(
+            r"
+RUBY VERSION
+   ruby 3.4.0.rc1
+
+BUNDLED WITH
+   2.3.4
+",
+        )
+        .unwrap();
+
+        assert_eq!(
+            info.bundler_version,
+            BundlerVersion::Explicit("2.3.4".to_string())
+        );
+        assert_eq!(
+            info.ruby_version,
+            RubyVersion::Explicit("3.4.0.rc1".to_string())
+        );
+    }
+
+    #[test]
+    fn test_preview_version() {
+        let info = GemfileLock::from_str(
+            r"
+RUBY VERSION
+   ruby 3.4.0.preview2
+
+BUNDLED WITH
+   2.3.4
+",
+        )
+        .unwrap();
+
+        assert_eq!(
+            info.bundler_version,
+            BundlerVersion::Explicit("2.3.4".to_string())
+        );
+        assert_eq!(
+            info.ruby_version,
+            RubyVersion::Explicit("3.4.0.preview2".to_string())
+        );
+    }
+
     #[test]
     fn test_parse_gemfile_lock() {
         let info = GemfileLock::from_str(