diff --git a/tools/idf_monitor.py b/tools/idf_monitor.py
index 8e4e372909..09deb0e7f4 100755
--- a/tools/idf_monitor.py
+++ b/tools/idf_monitor.py
@@ -276,6 +276,7 @@ class LinuxMonitor(Monitor):
 
     def serial_write(self, *args: str, **kwargs: str) -> None:
         self.serial.stdin.write(*args, **kwargs)
+        self.serial.stdin.flush()
 
     def check_gdb_stub_and_run(self, line: bytes) -> None:
         return  # fake function for linux target