细叶金丝桃（学名：Hypericum gramineum）为藤黄科金丝桃属下的一个种。

Hypericum gramineum, commonly known as small St. John's wort or grassy St. Johnswort, is an erect herb with a height of 10-40 cm. Its flowers are 5-12 mm in diameter. It is native to Australia (wherein it is found in every state and territory), New Caledonia, New Zealand, Papua New Guinea and parts of South–East Asia.