diff --git a/pkgs/tools/text/gawk/default.nix b/pkgs/tools/text/gawk/default.nix
index 001a50458e2..f865b69cfed 100644
--- a/pkgs/tools/text/gawk/default.nix
+++ b/pkgs/tools/text/gawk/default.nix
@@ -12,6 +12,7 @@ stdenv.mkDerivation rec {
   doCheck = !(
        stdenv.isCygwin # XXX: `test-dup2' segfaults on Cygwin 6.1
     || stdenv.isDarwin # XXX: `locale' segfaults
+    || stdenv.isSunOS  # XXX: `_backsmalls1' fails, locale stuff?
   );
 
   buildInputs = stdenv.lib.optional (stdenv.system != "x86_64-cygwin") libsigsegv
diff --git a/pkgs/tools/text/gnugrep/default.nix b/pkgs/tools/text/gnugrep/default.nix
index e8352e318b9..242ce36780d 100644
--- a/pkgs/tools/text/gnugrep/default.nix
+++ b/pkgs/tools/text/gnugrep/default.nix
@@ -15,7 +15,7 @@ stdenv.mkDerivation {
   buildInputs = [ pcre libiconv ];
 
   # cygwin: FAIL: multibyte-white-space
-  doCheck = !stdenv.isDarwin && !stdenv.isCygwin;
+  doCheck = !stdenv.isDarwin && !stdenv.isSunOS && !stdenv.isCygwin;
 
   # On Mac OS X, force use of mkdir -p, since Grep's fallback
   # (./install-sh) is broken.