One of the continuing problems faced in the society of Indonesia is the occurrence of interfaith marriage. Interfaith marriages that occur in Lombok are a social impact of a history and social relations between religions that have been running for a long time. This research was conducted with the aim of examine the regulations, practices, and the social impact of interfaith marriages that have occurred in Lombok. This study is non-doctrinal research where primer data were collected from related regulations and online interviews. The interview method using semi-structured interviews were conducted with the officers of the Lombok Population and Civil Registration Office, officers of Forum Kerukunan Umat Beragama (FKUB) and couples who have conducted interfaith marriages. Meanwhile, the secondary data were collected from article journals, books, reports, legal dictionaries and other documents. The Researcher found that Interfaith marriage regulations in Lombok applies the results of the Deliberations of religious leaders in 1984 on the agreement on procedures for solving problems between groups in the Regional Community Level 1 West Nusa Tenggara. This study also found that interfaith marriages occurred in Lombok are dominated by Islam and Hinduism religious communities which has happened since long ago due to the historical facts. This study discovered that interfaith marriage in Lombok gives effect to at least three impacts namely the social, religious and juridical side.