Solar PV is one of the fast-growing renewable energy in Thailand. Three sectors are contributing to solar PV installation, which are solar farms, industrial, and residential sector. However, the latter only contributes 1.39% of the cumulative capacity in 2016. By considering the lowering price of installation cost, growing affordable households, and a vast amount of solar irradiation in Thailand, it is of interest to observe the potential of the residential sector. Besides, there is a lack of study that focuses on the forecasting of residential solar PV in Thailand. Thus, this paper emphasizes on annual installation forecast of solar PV capacity in Thailand residential sector by using segmentation. This research categorizes residents into four categories, PV users with and without batteries, potential users, and rejecters, aimed to understand different types of users. An online survey of Thai residents about solar PV utilization was conducted from December 2017 to February 2018 to collect the data for the research. The results find that there is an exponential trend of increasing residential solar PV installation, followed by the reduction of payback period over time. It is forecasted about 3,511.4 MW of residential PV installation in the end of forecasting period. This research helps the decision maker to update the policies.