Desktop Tower Defense, or DTD, is a desktop tower defense game created by Paul Preece in March 2007. It was one of the first Tower Defense games that gave the user control over the maze by allowing the player place towers on the same map that the enemies walk on.

Desktop Tower Defense is played on a map resembling an office desktop. The player must stop a set number of enemies, known in the genre as "creeps", from reaching a set point on the playing field. This is accomplished by building and upgrading towers that shoot at, damage and kill the enemy creeps before they are able to reach their objective. Unlike many other tower defense games, the path of the creeps themselves is not set; instead, the towers built determine the path of the creeps, who take the shortest path they can find to the exit. The game does not allow the player to make an exit completely inaccessible, but key strategies revolve around guiding creeps into lengthy, meandering corridors.