For several generations, intermarriage has been common between indigenous Rotinese Christians and migrant Muslims and their descendants in the Indonesian village of Oelua on Roti Island. Muslims have engaged with the customary institutions upheld by indigenous Rotinese Christians—namely, those associated with marriage proposals and bridewealth. They have also engaged in reciprocal inter-household exchanges to raise the cash to pay for weddings and bridewealth, as well as for other life cycle events such as funeral feasts and gatherings in the post-funeral mourning period. This article argues that intermarriage and inter-household monetary exchanges are important, among other factors, in promoting low conflict relations between the two groups, primarily because of the regular opportunities generated to interact in both public and private spheres. Marriage preferences in Oelua are changing, however, with young Muslim men preferring to marry women who subscribe to the same religion and similar customs. Muslim attitudes are also changing with respect to their involvement in inter-household reciprocal exchanges, with many wanting to engage in different ways, or not at all. The article discusses what these changing attitudes and practices may mean for maintaining congenial inter-group relations between Christians and Muslims in the future.