War of the Planets (Italian: I Diafanoidi Vengono da Marte, lit. 'The Diaphanoids Come From Mars' is a 1966 Italian science fiction film, produced by Joseph Fryd and Antonio Margheriti, directed by Margheriti, that stars Tony Russel and Lisa Gastoni (Russel's name is misspelled in the opening credits as "Tony Russell"). The film was released theatrically in 1966 throughout Europe. Its storyline and screenplay were written by Ivan Reiner and Renato Moretti.

This is the second film in the Gamma-One series and follows Wild, Wild Planet (a.k.a. I Criminali della Galassia ("Criminals of the Galaxy")) and precedes War Between the Planets (a.k.a. Il Pianeta Errante ("Planet on the Prowl")) and Snow Devils (a.k.a. La Morte Viene dal Pianeta Aytin ("Death Comes From The Planet Aytin")).