Little Big Adventure is an action-adventure game developed by Adeline Software International and first released at the end of 1994. It was published in Europe by Electronic Arts and in North America, Asia and Oceania under the name Relentless: Twinsen's Adventure by Activision. Over 400,000 copies of the game were sold worldwide in the first release. The game was initially released on CD-ROM and some time later on floppy disks; the CD-ROM version featured full motion video, music and speech whereas the floppy disk version has MIDI music files and still images to replace the videos. The game was later ported to the PC-98 and FM Towns and released in Japan in 1995, for the PlayStation in Japan and Europe in 1996 and 1997 respectively, and to Android and iOS devices in 2014.

In 1997, a PC-only sequel was released under the name of Little Big Adventure 2 (also known as Twinsen's Odyssey).

On October 20th 2015, an "Enhanced Edition" developed by DotEmu was released on Steam, alongside a re-release of the original game.