This article is about theological views similar to those of Arius Aryan is an unrelated linguistic and ethnic concept. The term Arians may also refer to Polish brethren.

Arianism is most commonly used to refer to the theological positions made famous by the theologian Arius (c. AD 250-336), who lived and taught in Alexandria, Egypt, in the early 4th century. The most controversial of the teachings of Arius dealt with the relationship between God the Father and the person of Jesus and conflicted with trinitarian christological positions which came to dominate the Roman Church (and hence the modern Roman Catholic and Eastern Orthodox Churches and most other denominations).