diff --git a/src/output.c b/src/output.c
index 28ee298f..e1c615e7 100644
--- a/src/output.c
+++ b/src/output.c
@@ -518,11 +518,17 @@ verify_output_config_v1(const struct wlr_output_configuration_v1 *config)
 
 			if (wlr_output_is_wl(head->state.output) && refresh != 0) {
 				/* Wayland backend does not support refresh rates */
-				err_msg = "Wayland backend refresh rate unsupported";
+				err_msg = "Wayland backend refresh rates unsupported";
 				goto custom_mode_failed;
 			}
 		}
 
+		if (wlr_output_is_wl(head->state.output)
+				&& !head->state.adaptive_sync_enabled) {
+			err_msg = "Wayland backend requires adaptive sync";
+			goto custom_mode_failed;
+		}
+
 		/*
 		 * Ensure the new output state can be applied on
 		 * its own and inform the client when it can not.