diff --git a/src/Compilation.zig b/src/Compilation.zig
index d4d24e6640efd31032146b245c7a2bce64ba1fc1..e30914ee241039a64c3264874f6ee4b61f78b057 100644
--- a/src/Compilation.zig
+++ b/src/Compilation.zig
@@ -6291,8 +6291,6 @@ fn addCommonCCArgs(
                 // LLVM doesn't distinguish between Solaris and illumos, but the illumos GCC fork
                 // defines this macro.
                 .illumos => try argv.append("__illumos__"),
-                // This macro has not yet been upstreamed by SerenityOS to Clang.
-                .serenity => try argv.append("__serenity__"),
                 // Homebrew targets without LLVM support; use communities's preferred macros.
                 .@"3ds" => try argv.append("-D__3DS__"),
                 .wiiu => try argv.append("-D__WIIU__"),