Maru's Mission is an action video game released in 1991 by Jaleco for the original Game Boy. It was released in Japan as Oira Jajamaru! Sekai Daibōken (おいらじゃじゃ丸！～世界大冒険～, "I'm Jajamaru! World Adventure") on September 28, 1990. On January 18, 2012, it was released to the Japanese 3DS Virtual Console and later in North America on February 9, 2012.

It is the first game from the Jajamaru series, aside from the loosely related Ninja Taro, to be released in North America, until the release of Ninja JaJaMaru-kun through the Virtual Console. The soundtrack, as well as many sprites and some cut-scenes of the North American version are different from the original Japanese.

Maru's girlfriend Cori is kidnapped and hidden in a secret location. The player is Maru, and moves through six levels based on various folklore monsters.