diff --git a/rubygem-nokogiri.spec b/rubygem-nokogiri.spec
index 322835f..ecf5dc4 100644
--- a/rubygem-nokogiri.spec
+++ b/rubygem-nokogiri.spec
@@ -39,6 +39,8 @@ BuildRequires:	rubygem(pkg-config)
 BuildRequires:	libxml2-devel
 BuildRequires:	libxslt-devel
 BuildRequires:	ruby-devel
+# ruby27 needs this explicitly
+BuildRequires:	rubygem(racc)
 
 %description
 Nokogiri parses and searches XML/HTML very quickly, and also has