The aim of the present study was to determine the factor structure of the Positive Life Assets Scale (PLAS), a new measure to identify both internal and external life assets among high school students in Thailand, and to further examine the usefulness of the PLAS for a comprehensive, developmental, and strengths-based school and community integration program. A total of 12,200 high school students from 10 provinces within Thailand participated in the study. The factor structure of the PLAS was determined by first conducting an exploratory factor analysis on the 48-item scale and then using a confirmatory factor analysis to test the fit of the previously hypothesized factor structure of constructs assessed by the PLAS. The five factors extracted represented five major areas of the positive life assets as originally defined including powers of Community, Family, Peer, and Wisdom, which are external assets and power of Self, which is an internal asset. The five factors accounted for 49% of the total variance in PLAS scores. The analyses suggest that the tool can be a valid measure of positive life assets for high school students in Thailand. Future research efforts will include conducting additional studies to examine the construct validity of the PLAS.