Frère Jacques Beaulieu, OP (French pronunciation: [fʁɛʁ ʒɑk boljø]); 1651–1720), also known as Frère Jacques Baulot,^[1][2] was a travelling lithotomist with scant knowledge of anatomy and was also a Dominican friar. Beaulieu performed the frequently deadly procedure in France into the early 18th century.^[3]

The urologic community often claims Beaulieu is subject of the French nursery rhyme Frère Jacques (also known in English as Brother John), but this is not well-established. A possible connection between Frère Jacques and Beaulieu, as claimed by Irvine Loudon^[4] and many others, was explored by J. P. Ganem and C. C. Carson ^[5] without finding any evidence for a connection.

Some have suggested that Frère Jacques was instead written to mock the Jacobin monks of France (Jacobins are what the Dominicans are called in Paris).^[6]