Peter Riegert (born April 11, 1947) is an American actor, screenwriter, and film director.

Born in The Bronx, Riegert grew up in Hartsdale, NY, graduated Ardsley High School in 1964 and later from the University of Buffalo and worked at a number of jobs, including teaching, waiting tables, and social worker before settling on acting as a career. He made his Broadway debut in the musical Dance with Me. Other Broadway credits include The Old Neighborhood, An American Daughter, The Nerd, and Censored Scenes From King Kong. Off-Broadway he has appeared in Road to Nirvana, The Birthday Party, Isn't It Romantic, Sexual Perversity in Chicago, and A Rosen by Any Other Name.

Riegert's notable feature film credits include Animal House, Crossing Delancey, Local Hero, Chilly Scenes of Winter, Oscar, The Mask, Traffic (which won him the Screen Actors Guild Award for Outstanding Performance by the Cast of a Theatrical Motion Picture), and How to Kill Your Neighbor's Dog.

Riegert made his television debut as Cpl. Igor Straminsky in two episodes of M*A*S*H. He has also portrayed crooked New Jersey State Assemblyman Ronald Zellman in The Sopranos and defense attorney Chauncey Zeirko in multiple episodes of Law & Order: Special Victims Unit. He starred opposite former girlfriend Bette Midler in the television adaptation of Gypsy and was featured in the HBO drama Barbarians at the Gate (which earned him an Emmy Award nomination for Outstanding Supporting Actor in a Miniseries or a Special), the final episode of Seinfeld, and the television movie Back When We Were Grownups, and he voiced the character of Max Weinstein in the episode "When You Wish Upon a Weinstein" on Family Guy.

Riegert made his screenwriting and directorial debuts with By Courier, based on a short story by O. Henry. It received an Academy Award nomination for Best Live Action Short Film and won him the Festival Award for Best First Feature at the Marco Island Film Festival. He also wrote, directed, and starred in the full-length feature King of the Corner.

Made his professional debut playing Chico Marx in "Minnie's Boys," the musical based on The Marx Brothers.

Once was a school teacher teaching eighth grade.

Former boyfriend of Bette Midler; they lived together in the 1970s. He played perennial boyfriend Herbie to Midler's Mama Rose in "Gypsy" in the 1993 made-for-TV film version of the hit Broadway musical.

Played a wild, authority-hating frat brother in Animal House (1978) and a stiff, rigid, no-nonsense authoritarian cop in Mask, The (1994).