This Element provides a thorough overview of the free will debate as it currently stands. After distinguishing the main senses of the term 'free will' invoked in that debate, it proceeds to set out the prominent versions of the main positions, libertarianism, compatibilism, and free will skepticism, and then to discuss the main objections to these views. Particular attention is devoted to the controversy concerning whether the ability to do otherwise is required for moral responsibility and whether it is compatible with determinism, and to manipulation arguments against compatibilism. Two areas in which the free will debate has practical implications are discussed in detail, personal relationships and criminal justice.