The couple was joined by Gigi's mother Yolanda Hadid and Zayn's mother Trisha Malik, reported E! online.
Yolanda shared on Instagram a group picture of them celebrating the day.
They all flashed smiles to the camera.
"Eid Mubarak to everyone celebrating.......," Yolanda wrote in the caption.
Trisha re-posted the picture on her own Instagram page. "Eid Mubarak to everyone... #BlessedDay," so said.
Gigi, 22, and Zayn, 24, started dating in 2015.
They starred together on his music video for single "Pillowtalk".