Peter Farrelly and Bobby Farrelly, collectively referred to as the Farrelly brothers, are American screenwriters and directors. They have made eleven films together, including Dumb and Dumber, Outside Providence, and There's Something About Mary.

Say It Isn't So is a 2001 American black comedy film directed by J. B. Rogers, written by Peter Gaulke and Gerry Swallow, and starring Heather Graham and Chris Klein as two young lovers who come to believe that they are actually siblings.