diff --git a/oauth2.gemspec b/oauth2.gemspec
index 86a825c7..90ad0b7f 100644
--- a/oauth2.gemspec
+++ b/oauth2.gemspec
@@ -32,10 +32,9 @@ Gem::Specification.new do |spec|
 
   spec.require_paths = %w[lib]
   spec.bindir        = 'exe'
-  spec.executables   = spec.files.grep(%r{^exe/}) { |f| File.basename(f) }
-  spec.files         = `git ls-files -z`.split("\x0").reject do |f|
-    f.match(%r{^(bin|test|spec|features)/})
-  end
+  spec.files = Dir['lib/**/*', 'LICENSE', 'README.md', 'CHANGELOG.md', 'CODE_OF_CONDUCT.md']
+  spec.test_files = Dir['spec/**/*']
+  spec.executables = spec.files.grep(%r{^exe/}) { |f| File.basename(f) }
 
   spec.add_development_dependency 'addressable', '~> 2.3'
   spec.add_development_dependency 'backports', '~> 3.11'