diff --git a/Makefile b/Makefile
index b997dbfd..ff8dcf6d 100644
--- a/Makefile
+++ b/Makefile
@@ -257,7 +257,7 @@ tidy: src/asm/parser.hpp src/link/script.hpp
 iwyu:
 	$Qenv ${MAKE} \
 		CXX="include-what-you-use" \
-		REALCXXFLAGS="-std=c++20 -I include"
+		REALCXXFLAGS="-std=c++2a -I include"
 
 # Target used in development to conveniently invoke RGBDS binaries with Wine.
 wine-shim:
diff --git a/compile_flags.txt b/compile_flags.txt
index 6b8032ce..4cdeefd4 100644
--- a/compile_flags.txt
+++ b/compile_flags.txt
@@ -1,4 +1,4 @@
--std=c++20
+-std=c++2a
 -I
 include
 -fno-exceptions