diff --git a/pkgs/applications/networking/browsers/chromium/common.nix b/pkgs/applications/networking/browsers/chromium/common.nix
index 420dc5811c7..167fe072ee5 100644
--- a/pkgs/applications/networking/browsers/chromium/common.nix
+++ b/pkgs/applications/networking/browsers/chromium/common.nix
@@ -292,6 +292,11 @@ let
       runHook postConfigure
     '';
 
+    # Don't spam warnings about unknown warning options. This is useful because
+    # our Clang is always older than Chromium's and the build logs have a size
+    # of approx. 25 MB without this option (and this saves e.g. 66 %).
+    NIX_CFLAGS_COMPILE = "-Wno-unknown-warning-option";
+
     buildPhase = let
       # Build paralelism: on Hydra the build was frequently running into memory
       # exhaustion, and even other users might be running into similar issues.