Nusa Tenggara Timur (the Lesser Sunda Islands), an archipelago of more than 2,000,000 km^2, contains diverse ethnic groups and dwelling types. This paper reveals the findings of field visits to East Timor and Sumba, Indonesia (2012), West Timor and East Timor (2014), and Flores, Rote, and Savu (2019). Firstly, it finds that pairings of uma lulik (sacred houses) and uma tidor (ordinary houses) are common on Timor Island, with each of Timor's fourteen ethnic groups having its own innovative concepts and construction techniques. Secondly, it finds that the "round houses" of Timor Island and Flores Island are quite unique compared to other dwellings in the Indonesian archipelago; eight groups have adopted round or oval forms for their uma lulik. Thirdly, the center spaces of houses are attractive and interesting for survey and discussion. "Hearth-centered" houses can readily be seen in Sumba, Timor, Flores, Rote and Savu. Indeed, this archetype and its derived forms cover most of the house types in the Lesser Sunda Islands, an obvious regional feature that contrasts with the hearth-behind house type of the Bugis (Sulawesi) and Javanese (Java) and the multi-hearth-inside house type of the Batak Karo (Sumatra) and Iban (Kalimantan).