diff --git a/digest-crc.gemspec b/digest-crc.gemspec
index dec089e..268c590 100644
--- a/digest-crc.gemspec
+++ b/digest-crc.gemspec
@@ -24,7 +24,7 @@ Gem::Specification.new do |gem|
 
   glob = lambda { |patterns| gem.files & Dir[*patterns] }
 
-  gem.files = `git ls-files`.split($/)
+  gem.files = `git ls-files`.split($/).grep_v(/^spec\//)
   gem.files = glob[gemspec['files']] if gemspec['files']
 
   gem.executables = gemspec.fetch('executables') do