PixelJunk Monsters is a second game in the PixelJunk series developed by Q-Games for the PlayStation 3. It was released worldwide on the PlayStation Store on January 24, 2008. The game was released for the PlayStation Portable under the title PixelJunk Monsters Deluxe.

Gameplay in PixelJunk Monsters has similarities to various tower defense titles. The objective is to build defense towers along the enemies' path to keep them from reaching a hut, or base. Several small creatures dwell at the base. For each enemy that survives the defense towers and reaches the hut, one creature is killed. If all creatures are wiped out, the level is failed.

Towers have distinct attributes, such as rapid fire, long range, air-focused, etc. Destroyed enemies usually drop coins and occasionally give gems, which then can be used to upgrade and research new towers.

There is a total of 21 different levels (36 with the expansion pack) at 3 stages of difficulty. There are also 3 special stages that unlock unique abilities for the player character. Several "Trophy Challenges" were also added to the game after a patch.

Unlike more traditional tower defense games, the player controls a character around the screen, collecting coins and building towers. This replaces the standard cursor controls. A second player can also join in and assist in building towers.

In PixelJunk Monsters Online, the player controls either Tikiman or Tikigirl.