There has been little research done on explaining the ethnic tolerance behavior from the perspective of sociological theories. The authors chose rational choice theory and the theory of planned behavior as they are widely used in explaining the human social behaviour. In this article, the theories are used to explain the effects of religion on ethnic tolerance in Malaysia. The authors also reviewed a number of literatures to study how religion is associated with ethnic tolerance. From the rational choice theory perspective, it was found that ethnic tolerance can be influenced by one's religious belief if those who practice it are reciprocated with the promise of retributions from God. The theory of planned behavior on the other hand suggests that religion can affect behavior, subjective norms, and perception on how one deals with ethnic tolerance. It is recommended that the theories are used by future studies in order to further expand knowledge base on the subject of ethnic tolerance. This study provides ways and means to inculcate ethnic integration in Malaysia and helps to diffuse religious and ethnic prejudices.