The show, which opened on April 18 after a month of previews, will now play until Sept. 4. It was to have closed on June 12.
Though it opened to mixed reviews, Piazza has since become a favorite of New York's awards organizations. It led the Outer Critics Circle Awards nominations with 11 nods, while the Drama Desk organization also nominated it in 11 categories.
Craig Lucas penned the book for the show, which has already been seen in stagings at both Seattle's Intiman Theatre and, more recently, at Chicago's Goodman Theatre.
The Light in the Piazza is a love story of a young American woman, Clara (Kelli O'Hara), who, while on holiday, falls for a young Italian man. When the young woman's mother (Victoria Clark) learns of the affair, she opposes it for unknown reasons. The musical is set in Florence and Rome in the summer of 1953.
The cast of 18 also includes Glenn Seven Allen, David Bonanno, David Burnham, Laura Griffith, Prudence Wright Holmes, Jennifer Hughes, Felicity LaFortune, Catherine LaValle, Michel Moinot and Joseph Siravo.
The creative team includes Ted Sperling (musical direction), Michael Yeargan (sets), Catherine Zuber (costumes) and Christopher Akerlind (lights).
Piazza is based on Elizabeth Spencer's 1960 novella.