John Phillips penned the script, which follows a lewd Army veteran (De Niro) who tricks his uptight grandson (Efron) into taking him down to Florida to mingle with party-crazed college kids on Spring Break. Plaza is set to play Lenore, a spellbinding wild child and the romantic lead opposite De Niro.
The actress is best known for starring alongside Amy Poehler on over 100 episodes of NBC's "Parks and Recreation," which returns for its final season on Jan. 13. But Plaza has carved out a career on the big screen, too, including a starring role in Colin Trevorrow's "Safety Not Guaranteed." She's no stranger to raunchy comedies, either, having starred as a sex-deprived college coed in Maggie Carey's "The To Do List." Most recently, Plaza starred on Lifetime's TV movie "Grumpy Cat's Worst Christmas Ever."
Other recently announced co-stars include Zoey Deutch ("Vampire Academy") and Dermot Mulroney ("My Best Friend's Wedding.")
Bill Block's QED International, Jason Barrett, Barry Josephson, Michael Simkin and Running Wild are producing "Dirty Grandpa," which was previously titled "Driving Dick Kelly." Lionsgate is distributing the film, set for an Aug. 12, 2016 release.
The Schiff Company and CAA represent Plaza.
Deadline first reported the casting.