Religious conversion is the adoption of a set of beliefs identified with one particular religious denomination to the exclusion of others. Thus "religious conversion" would describe the abandoning of adherence to one denomination and affiliating with another. This might be from one to another denomination within the same religion, for example, from Protestant Christianity to Roman Catholicism or from Sunnī Islam to Shīʿa Islam. In some cases, religious conversion "marks a transformation of religious identity and is symbolized by special rituals".

A deathbed conversion is the adoption of a particular religious faith shortly before dying. Making a conversion on one's deathbed may reflect an immediate change of belief, a desire to formalize longer-term beliefs, or a desire to complete a process of conversion already underway. Claims of the deathbed conversion of famous or influential figures have also been used in history as rhetorical devices.