Gradius Galaxies is a horizontally-scrolling shooter handheld video game released for the Game Boy Advance. This is the only Gradius title available for the system.

The game's plot is set between Gradius III and Gradius Gaiden. Bacterion was developing a powerful weapon to use against the planet Gradius, but it was destroyed. A few years later it crashed on a planet and the planet gradually changed into a mechanical fortress. The planet Gradius then sent the Vic Viper to stop it.