diff --git a/pkgs/development/libraries/fontconfig/make-fonts-cache.nix b/pkgs/development/libraries/fontconfig/make-fonts-cache.nix
index 1c88235b925..2ee0af8cfc1 100644
--- a/pkgs/development/libraries/fontconfig/make-fonts-cache.nix
+++ b/pkgs/development/libraries/fontconfig/make-fonts-cache.nix
@@ -4,6 +4,7 @@ runCommand "fc-cache"
   rec {
     buildInputs = [ fontconfig.bin ];
     preferLocalBuild = true;
+    allowSubstitutes = false;
     passAsFile = [ "fontDirs" ];
     fontDirs = ''
       <!-- Font directories -->