Molly Peskin-Suso is the cousin of Abby Suso, who appears in the book Simon vs. the Homo Sapiens Agenda.

This is in stark contrast to her twin sister, Cassie, who has not only kissed plenty of girls, but has her first girlfriend, Mina.

[6] Writing for The Booklist, Michael Cart notes that Albertalli has captured "the agonies and ecstasies of adolescent love."

[8] NPR's Caitlyn Paxson writes that The Upside of Unrequited is a "snappy romance" and "fresh, snarky, and poignant.

[13] In July 2024, Variety reported Ayvan Williams, Jessica Belkin, and Savannah Lee Smith are set to portray the principal cast, with the film entering production summer 2024.

[14] Later in July, Deadline reported that Siena Agudong, Luke Eisner, Noah Lomax, Patrick Luwis, and Matthew Sato joined the cast.