Captain Lionel George Carroll, 16th Baron Petre (3 November 1890 – 30 September 1915) was an English peer.
In 1908, he became engaged to Catherine Margaret Boscawen (1891–1983), granddaughter of the 6th Viscount Falmouth, taking a diamond from an earring of the Petre jewels to make the ring.
He served in France and Belgium, but died at Paris-Plage on 30 September 1915 of wounds received in action at the Battle of Loos.
[2] Through his mother Julia, Lord Petre is a relative of the American Carroll family of Maryland, who were prominent Catholics and Patriots in a largely Protestant society.
A notable ancestor is Charles Carroll of Carrollton, the only Catholic signatory of the Declaration of Independence.