diff --git a/gems/aws-sigv4/CHANGELOG.md b/gems/aws-sigv4/CHANGELOG.md
index 5d888d9b841..41b74dc844a 100644
--- a/gems/aws-sigv4/CHANGELOG.md
+++ b/gems/aws-sigv4/CHANGELOG.md
@@ -1,6 +1,8 @@
 Unreleased Changes
 ------------------
 
+* Issue - Add missing require of `pathname` to `Signer`.
+
 1.9.0 (2024-07-23)
 ------------------
 
diff --git a/gems/aws-sigv4/lib/aws-sigv4/signer.rb b/gems/aws-sigv4/lib/aws-sigv4/signer.rb
index a435695443f..e1083939efd 100644
--- a/gems/aws-sigv4/lib/aws-sigv4/signer.rb
+++ b/gems/aws-sigv4/lib/aws-sigv4/signer.rb
@@ -6,6 +6,7 @@
 require 'uri'
 require 'set'
 require 'cgi'
+require 'pathname'
 require 'aws-eventstream'
 
 module Aws