This study aims at examining the effect of organizational culture, transformational leadership and working motivation to the performance of school supervisors when tested both individually and simultaneously. Variables of organizational culture, transformational leadership and working motivation are treated as independent variables that mold the level of performance of school supervisors as a dependent variable. The research was conducted on proportional randomly selected 231 school supervisors in Jambi Province, Indonesia. Using mix method, a sequential explanatory design is applied where quantitative come first. The study both quantitatively and qualitatively reveals that there is a positive significant relationship among variables under the following distribution of coefficient of correlation: organizational culture to performance of school supervisors =0.4123, transformational leadership to performance of school supervisors=0.4364, working motivation to performance of school supervisors = 0.3842, and when tested together it produces coefficient of determination = 0.2340 indicating the existence of other 76.6 % variables not including in the model affecting performance of school supervisors