The name Gatsby is a boy's name of German origin. Gatsby and is often added to lists like American Names for Boys and discussed in our forums with posts like "Boys Drop 2 Add 1 pick a favor that can't be dropped".
From the experts:
Suddenly, we're hearing the name Gatsby, as in The Great character by F. Scott Fitzgerald, used as a first name for girls as well as boys. The book's Jay Gatsby gussied up his surname from Gatz, whose meaning is given variously as left-handed, cat, God, and person from Gat. As a first name, it's got a lot of energy and that great pedigree.