This Element addresses the opportunities and constraints operating on monotheistic peacebuilding, focusing on the three Abrahamic faiths, Christianity, Judaism, and Islam, which share a common origin. These opportunities and constraints are approached through what the volume calls 'the paradox of monotheism'. Monotheism is defined by belief in one omnipotent, benign, and loving God, but this God does not or cannot prevent violence, war, and conflict. Moreover, monotheism can actually promote conflict between the Abrahamic faiths, and with other world religions, giving us the puzzle of holy wars fought in God's name. The first section of the Element outlines the paradox of monotheism and its implications for monotheistic peacebuilding; the second section addresses the peacebuilding efforts of three Abrahamic monotheistic religions and the constraints that operate as a result of the paradox of monotheism. This paradox tends to limit monotheistic peacebuilding to inter-faith dialogue, which often does not go far enough.