This research intended to investigate factors and associated indicators of STEM educational administration for extra-large size secondary schools. The researchers conceptualized the factors and indicators by examining related documents and cross-examining with 11 experts to confirm them. A quantitative research design using questionnaire to collect data from 480 respondents consisted of 15 school administrators and 465 teachers. The results indicated that goodness of fit for the identified factors and indicators were compliance with empirical data: χ² = 77.869, df = 63, χ²/df = 1.236, p-value = 0.098, RMSEA = 0.022, SRMR = 0.022, CFI = 0.998, TLI = 0.995.