diff --git a/Library/Homebrew/download_strategy.rb b/Library/Homebrew/download_strategy.rb
index 103b3a314c..d9a6e86290 100644
--- a/Library/Homebrew/download_strategy.rb
+++ b/Library/Homebrew/download_strategy.rb
@@ -703,7 +703,12 @@ class CurlGitHubPackagesDownloadStrategy < CurlDownloadStrategy
     meta[:headers] ||= []
     # GitHub Packages authorization header.
     # HOMEBREW_GITHUB_PACKAGES_AUTH set in brew.sh
-    meta[:headers] << "Authorization: #{HOMEBREW_GITHUB_PACKAGES_AUTH}"
+    # If using a private GHCR mirror with no Authentication set then do not add the header. In all other cases add it.
+    if !Homebrew::EnvConfig.artifact_domain.presence ||
+       Homebrew::EnvConfig.docker_registry_basic_auth_token.presence ||
+       Homebrew::EnvConfig.docker_registry_token.presence
+      meta[:headers] << "Authorization: #{HOMEBREW_GITHUB_PACKAGES_AUTH}"
+    end
     super
   end