In the philosophy of religion, the problem of evil is the question of how to reconcile the existence of evil with that of a deity who is omnipotent, omniscient and omnibenevolent (see theism). An argument from evil attempts to show that the co-existence of evil and such a deity is unlikely or impossible, and attempts to show the contrary have been traditionally known as theodicies.

There are a wide range of responses that have been given to the problem of evil. These include the explanation of evil as the result of free will misused by God's creatures, the view that our suffering is required for personal growth, the denial that God is omnipotent, omniscient, or omnibenevolent, and skepticism concerning the ability of humans to understand God's reasons for permitting the existence of evil. There are also many discussions of "evil" and associated "problems" in other philosophical fields, such as secular ethics, and scientific disciplines such as evolutionary ethics. But as usually understood, the "problem of evil" is posed in a theological context.