--- a/bazel/envoy_build_system.bzl
+++ b/bazel/envoy_build_system.bzl
@@ -128,6 +128,9 @@
         targets = ["", "install"],
         **kwargs):
     cache_entries.update(default_cache_entries)
+    if generate_args == ["-G", "Ninja"]:
+        # rules_foreign_cc expects the generator as one argument, e.g. "-GNinja".
+        generate_args = ["-GNinja"]
     cache_entries_debug = dict(cache_entries)
     cache_entries_debug.update(debug_cache_entries)