Evil temples (synonyms: corrupt churches, evil cathedrals; example toponyms: Blood Church, Temple of the Night) are temples dedicated to evil gods or evil magics. They may contain sacrificial altars, torture chambers, dungeons, blood pools, and dungeon cells to hold unwilling participants. There may be cult chambers. There may be candles and magic or occult symbols. Often evil temples are located in inhospitable or threatening terrain, such as at the mouth of an active volcano, within a skull rock, or on a hidden island. They are home to cultists, evil clerics, and monsters from other realms.

In game worlds, evil temples are often dungeons.

When designing evil temples, consider the god or religion for which they were constructed. Often in fictional worlds evil temples serve as a means to bring forth an apocalypse, summon a cosmic monster to this dimension or awaken them from a slumber, or fulfil or end a prophecy.

Evil temples are often used in game worlds, and may be sites of traps, for instance flame traps, blade traps, or pitfall traps.