Lieutenant General Sir Thomas Molyneux, 1st Baronet FRS (14 April 1661 – 19 October 1733) was an Irish physician.

Educated at Trinity College, Dublin, he became a doctor with an MA and MB in 1683, aged 22.

He went to Europe and continued his medical studies, resulting in gaining the MD degree in 1687.

Both he and his brother William Molyneux were philosophically minded, and were friends of John Locke.

He was buried in St. Audoen's Church, Dublin,[4][1] and there is a fine monument to him in Armagh Cathedral by the sculptor Roubiliac, with an elaborate description of his honours and genealogy.