Patriarchal interpretations of religions have given rise to purity cultures which are selectively oppressive, dangerous, and sexually restrictive to women. Furthermore, patriarchal versions of religions have led to the development of pervasive rape cultures, beliefs that normalize sexual violence and shame the victims. By studying Christian and Islamic scriptures, theological doctrines, and traditional practices concerning women and sex, this thesis will demonstrate how these religions have been utilized in sexually oppressive societies. The societal attitudes and practices derived from oppressive religious stances are harmful to women, both socially and physically, by oppression and rape. Before the horrors of purity and rape cultures can be fought, the culpability of religions and their patriarchal interpretations should be understood.