Idolatry is the worship of a cult image or "idol" as though it were God. In Abrahamic religions (namely Judaism, Samaritanism, Christianity, the Baháʼí Faith, and Islam) idolatry connotes the worship of something or someone other than the Abrahamic god as if it were God. In these monotheistic religions, idolatry has been considered as the "worship of false gods" and is forbidden by texts such as the Ten Commandments. Other monotheistic religions may apply similar rules.

For instance, the phrase false god is a derogatory term used in Abrahamic religions to indicate cult images or deities of non-Abrahamic Pagan religions, as well as other competing entities or objects to which particular importance is attributed. Conversely, followers of animistic and polytheistic religions may regard the gods of various monotheistic religions as "false gods" because they do not believe that any real deity possesses the properties ascribed by monotheists to their sole deity. Atheists, who do not believe in any deities, do not usually use the term false god even though that would encompass all deities from the atheist viewpoint. Usage of this term is generally limited to theists, who choose to worship some deity or deities, but not others.

In many Indian religions, which include Hinduism, Buddhism, and Jainism, idols (murti) are considered as symbolism for the absolute but not the Absolute, or icons of spiritual ideas, or the embodiment of the divine. It is a means to focus one's religious pursuits and worship (bhakti). In the traditional religions of Ancient Egypt, Greece, Rome, Africa, Asia, the Americas and elsewhere, the reverence of cult images or statues has been a common practice since antiquity, and cult images have carried different meanings and significance in the history of religion. Moreover, the material depiction of a deity or more deities has always played an eminent role in all cultures of the world.

The opposition to the use of any icon or image to represent ideas of reverence or worship is called aniconism. The destruction of images as icons of veneration is called iconoclasm, and this has long been accompanied with violence between religious groups that forbid idol worship and those who have accepted icons, images and statues for veneration. The definition of idolatry has been a contested topic within Abrahamic religions, with many Muslims and most Protestant Christians condemning the Catholic and Eastern Orthodox practice of venerating the Virgin Mary in many churches as a form of idolatry.

The history of religions has been marked with accusations and denials of idolatry. These accusations have considered statues and images to be devoid of symbolism. Alternatively, the topic of idolatry has been a source of disagreements between many religions, or within denominations of various religions, with the presumption that icons of one's own religious practices have meaningful symbolism, while another person's different religious practices do not.