diff --git a/lib/bundler/installer/standalone.rb b/lib/bundler/installer/standalone.rb
index e8494b4bcd..2aba648e77 100644
--- a/lib/bundler/installer/standalone.rb
+++ b/lib/bundler/installer/standalone.rb
@@ -29,7 +29,9 @@ module Bundler
       @specs.map do |spec|
         next if spec.name == "bundler"
         Array(spec.require_paths).map do |path|
-          gem_path(path, spec).sub(version_dir, '#{RUBY_ENGINE}/#{RbConfig::CONFIG["ruby_version"]}')
+          gem_path(path, spec).
+            sub(version_dir, '#{RUBY_ENGINE}/#{RbConfig::CONFIG["ruby_version"]}').
+            sub(extensions_dir, 'extensions/\k<platform>/#{RbConfig::CONFIG["ruby_version"]}')
           # This is a static string intentionally. It's interpolated at a later time.
         end
       end.flatten.compact
@@ -39,6 +41,10 @@ module Bundler
       "#{RUBY_ENGINE}/#{RbConfig::CONFIG["ruby_version"]}"
     end
 
+    def extensions_dir
+      %r{extensions/(?<platform>[^/]+)/#{RbConfig::CONFIG["ruby_version"]}}
+    end
+
     def bundler_path
       Bundler.root.join(Bundler.settings[:path], "bundler")
     end
diff --git a/spec/bundler/install/gems/standalone_spec.rb b/spec/bundler/install/gems/standalone_spec.rb
index 0bbd829148..f856d6b51e 100644
--- a/spec/bundler/install/gems/standalone_spec.rb
+++ b/spec/bundler/install/gems/standalone_spec.rb
@@ -202,8 +202,9 @@ RSpec.shared_examples "bundle install --standalone" do
     it "generates a bundle/bundler/setup.rb with the proper paths" do
       expected_path = bundled_app("bundle/bundler/setup.rb")
       extension_line = File.read(expected_path).each_line.find {|line| line.include? "/extensions/" }.strip
+      platform = Gem::Platform.local
       expect(extension_line).to start_with '$:.unshift File.expand_path("#{__dir__}/../#{RUBY_ENGINE}/#{RbConfig::CONFIG["ruby_version"]}/extensions/'
-      expect(extension_line).to end_with '/very_simple_binary-1.0")'
+      expect(extension_line).to end_with platform.to_s + '/#{RbConfig::CONFIG["ruby_version"]}/very_simple_binary-1.0")'
     end
   end