This study aims to develop a standard instrument for measuring mental health among urban adolescents in Indonesia. The objective is to produce valid and reliable school adolescent mental health instruments to be used by agencies or schools to identify students' mental health. The survey was conducted in Jakarta and South Tangerang with a total of 1007 respondents divided into two experiments where the first trial was conducted on 597 students and the second trial was conducted on 410 students. Measurements were made using a Likert scale questionnaire. Instrument testing begins with a theoretical validity test by 4 experts and 20 panelists who test the instrument material in terms of construction, content and language. Experts analyze and correct the instrument qualitatively. The instrument was then reviewed and analyzed quantitatively by panelists using the Aiken index. At this stage, 44 items, 9 indicators and 3 variable dimensions were obtained. The next test is done by testing the validity empirically, by analyzing the measurement model using Confirmatory Factor Analysis (CFA) with the LISREL 8.80 Full Version program. By using the criteria for the SLF value [greater than or equal to]0.30 and t-value [greater than or equal to]1.96, and calculating the reliability with the construct reliability (CR) at the level> 0.70, the results of the second trial showed that 35 items were valid. The observations of the model fitness through Goodness-of-Fit test showed that there is a fitness between the theoretical model and the empirical model for the mental health instruments in this study.