Efforts to understand psychological capital (PsyCap) in positive psychological intervention efforts in education are believed to improve teacher performance. The development of a PsyCap scale in vocational education is very important because it has not been widely implemented in Indonesia. This study aims to develop a new, valid, and reliable Teachers' Psychological Capital Scale (TPCS) based on a psychometric approach uses research development. In all, there are nine processes involved in the three stages (item development, scale development, and scale evaluation) of establishing a rigorous scale. Data analysis to test the validity of the items using structural equation models (SEM) with confirmatory factor analysis (CFA) techniques. The TPCS measurement tool consists of 24 items that describe four dimensions, i.e. self-efficacy, optimism, hope, and resilience. The research subjects were vocational school teachers (N = 300) spread across 10 districts in Indonesia. The results of the study show that the PsyCap measurement model fits significantly with the data, meaning that TPCS has strong psychometric feasibility and the deviation from the existing measurements is not substantial. Thus, TPCS is suitable for assessing teachers' PsyCap in a more general sense. Further research into TPCS is made easier now that scientists and practitioners have a deeper grasp of the ontology and technique of scale building and validation thanks to this work.