John Cassini (born in Toronto) is a Canadian actor.

Cassini appeared in the 1995 Brad Pitt film Seven. He starred in the 2005 film Cool Money. Cassini starred as Ronnie Delmarco on the CBC series Intelligence, which was cancelled on March 7, 2008.

He guest-starred in the CW series Arrow and on the USA network original series Motive in April, 2016.

Cassini appeared in and is listed as a producer of the film Guido Superstar: The Rise of Guido, starring, produced, and directed by Silvio Pollio, including, Nicholas Lea, Terry Chen, and Michael Eklund. The film screened at the 2010 Vancouver International Film Festival.

Cassini is an Italian citizen.