diff --git a/pkgs/applications/misc/k2pdfopt/default.nix b/pkgs/applications/misc/k2pdfopt/default.nix
index 8f69abd3a98..2a3b2e61fc2 100644
--- a/pkgs/applications/misc/k2pdfopt/default.nix
+++ b/pkgs/applications/misc/k2pdfopt/default.nix
@@ -104,6 +104,10 @@ stdenv.mkDerivation rec {
 
   cmakeFlags = [ "-DCMAKE_C_FLAGS=-I${src}/include_mod" ];
 
+  NIX_LDFLAGS = [
+    "-lpthread"
+  ];
+
   installPhase = ''
     install -D -m 755 k2pdfopt $out/bin/k2pdfopt
   '';