The term Western religion refers to religions that originated within Western culture, and are thus which historically, culturally, and theologically distinct from the Eastern religions. The contrast between Western and Eastern religions largely pertains to the distinction between monotheism and polytheism, respectively, and the term Abrahamic religion is often used in lieu of using the East and West terminology.

Western culture itself was significantly developed through the emergence of Christianity as it was introduced in the Roman Empire in the late 4th century and evolved in the course of the European Middle Ages, and the term "Christendom" largely indicates this intertwined history. Western Christianity was significantly influenced by Hellenistic religion (notably Platonism and Gnosticism) as well as the Roman imperial cult. Western Christianity is based on Roman Catholicism (Latin Rite), as opposed to Eastern Orthodoxy, from which it was divided by the Great Schism of the 11th century, and further includes all Protestant traditions splitting off Roman Catholicism from the 16th century.