diff --git a/xwayland/selection/incoming.c b/xwayland/selection/incoming.c
index ab06f40dd..b2df3b537 100644
--- a/xwayland/selection/incoming.c
+++ b/xwayland/selection/incoming.c
@@ -31,7 +31,7 @@ static int xwm_data_source_write(int fd, uint32_t mask, void *data) {
 		return 1;
 	}
 
-	wlr_log(L_DEBUG, "wrote %ld (chunk size %ld) of %d bytes",
+	wlr_log(L_DEBUG, "wrote %zd (chunk size %zd) of %d bytes",
 		transfer->property_start + len,
 		len, xcb_get_property_value_length(transfer->property_reply));
 
diff --git a/xwayland/selection/outgoing.c b/xwayland/selection/outgoing.c
index b612b2fbb..6d7565e34 100644
--- a/xwayland/selection/outgoing.c
+++ b/xwayland/selection/outgoing.c
@@ -96,7 +96,7 @@ static int xwm_data_source_read(int fd, uint32_t mask, void *data) {
 		goto error_out;
 	}
 
-	wlr_log(L_DEBUG, "read %ld bytes (available %zu, mask 0x%x)", len,
+	wlr_log(L_DEBUG, "read %zd bytes (available %zu, mask 0x%x)", len,
 		available, mask);
 
 	transfer->source_data.size = current + len;