Herbert Weir Smyth (August 8, 1857 – July 16, 1937) was an American classical scholar.

His comprehensive grammar of Ancient Greek has become a standard reference on the subject in English, comparable to that of William Watson Goodwin, whom he succeeded as Eliott Professor of Greek Literature at Harvard University.

From 1899 to 1900, he was professor of the Greek language and literature at the American Classical School at Athens.

From 1889 to 1904, he was secretary of the American Philological Association and editor of its Transactions and in 1904 was elected president.

He died in Bar Harbor, Maine on July 16, 1937, and was buried at Mount Auburn Cemetery.