Using detailed field survey and ethnographic data, this chapter examines the effective use of passive design in the traditional Cham house in the Mekong Delta to support a harmonious integration with the region’s climate and environment. The Cham people are not native to the Mekong Delta, having only began forming settlements in the region during the fifteenth century. Over time, the Cham have successfully adapted to life in the delta, while maintaining their ethnic identity and religious practices. We examine a key instrument employed by the Cham to harmoniously integrate with the riverine environment and climate of the Mekong Delta, namely, passive design in the traditional Cham house, which in fact persists to the present day. As the Mekong Delta undergoes tremendous developmental transformation over the past few decades, so did the Cham dwellings. We find it pertinent to understand how these traditional passive design works in order to go beyond seeing the architectural form of the traditional Cham house as a tangible heritage worth preserving. Instead, we can begin to recognize how these passive design elements function as a way in which Cham people have been living with heritage upon migrating to the Mekong Delta.