diff --git a/ruby.spec b/ruby.spec
index 925f62e..66a8c72 100644
--- a/ruby.spec
+++ b/ruby.spec
@@ -184,6 +184,7 @@ BuildRequires: procps
 %{?with_hardening_test:BuildRequires: %{_bindir}/checksec}
 BuildRequires: multilib-rpm-config
 BuildRequires: gcc
+BuildRequires: zlib-devel
 
 # This package provides %%{_bindir}/ruby-mri therefore it is marked by this
 # virtual provide. It can be installed as dependency of rubypick.