The objectives of this research are to develop key performance indicators for measuring the knowledge competency of technical teachers in Thailand and to analyze it by subject department. The research samples are 360 vocational teachers from 6 subject departments: machine tool technology, mechanical power technology, electrical power, electronic technology, welding, and civil construction, all affiliated with the Office of the Vocational Education Commission. Stratified random sampling technique is used to select the sample out of a population of 782. The research instrument used is a 5-rating scale questionnaire with reliability of 0.94. Data analysis is done using confirmatory factor analysis, mean, standard deviation, and analysis of variance (One-way ANOVA). The research results found that (1) there are 18 key performance indicators for measuring the knowledge competency of technical teachers, with the goodness of fit index passed all good criteria: Chi-square = 72.490, df = 56, p-value = 0.068, GFI = 0.987, AGFI = 0.965, and RMSEA = 0.022, and (2) technical teachers affiliated with the Office of the Vocational Education Commission in different subject departments, when analyzed, show no differences in teaching competency.