diff --git a/thunderbird.spec b/thunderbird.spec
index 194c556..adca655 100644
--- a/thunderbird.spec
+++ b/thunderbird.spec
@@ -62,6 +62,7 @@ BuildRequires:	libpng-devel, libjpeg-devel, gtk2-devel
 BuildRequires:	zlib-devel, gzip, zip, unzip
 BuildRequires:  nspr-devel >= %{nspr_version}
 BuildRequires:  nss-devel >= %{nss_version}
+BuildRequires:  nss-pkcs11-devel >= %{nss_version}
 BuildRequires:	libIDL-devel
 BuildRequires:	tcsh
 BuildRequires:	freetype-devel