Diablo II is a hack and slash action role-playing video game, developed by Blizzard North and published by Blizzard Entertainment in 2000 for Windows and Mac OS computers.

The game, with its dark fantasy and horror themes, was conceptualized and designed by David Brevik and Erich Schaefer, who with Max Schaefer acted as project leads on the game. The producers were Matthew Householder and Bill Roper.

Building on the success of its predecessor Diablo (1996), Diablo II was one of the most popular games of 2000. Major factors that contributed to Diablo II's success include its continuation of popular fantasy themes from the previous game and its access to Blizzard's free online play service Battle.net. An expansion to Diablo II, Diablo II: Lord of Destruction, was released in 2001. A sequel, Diablo III, was announced in 2008, and was released on May 15, 2012.

The storyline of original Diablo II progresses through four chapters or acts. Each act following a more or less predetermined path, although there is some random-level generation in wilderness areas and dungeons between key cities. There are a list of quests which are usually required to advance the story, though some are optional. In contrast to the first Diablo whose levels consisted of descending deeper and deeper into a Gothic-themed dungeon and Hell, Diablo II's style is much more varied. While Act I is similar to the original, Act II mimics Ancient Egypt desert while Act III is supposedly based on the Maya civilization jungles. Act IV takes place in Hell and is the shortest, with just three quests compared to the other Acts that have six. The Lord of Destruction expansion adds Act V which continues the story where Act IV left off.