日本树莺（学名：Cettia diphone）为鹟科树莺属的鸟类。该物种的模式产地在日本小笠原群岛。

The Japanese bush warbler (Horornis diphone), known in Japanese as uguisu (ウグイス), is an Asian passerine bird more often heard than seen. Its distinctive breeding call can be heard throughout much of Japan from the start of spring.