The present study analyses the link between self-development and job performance of secondary school principals in Isfahan. The study is applied in terms of purpose and done by a qualitative-quantitative combined method. In the qualitative section, we use the thematic analysis strategy and in the quantitative section, we test the proposed research model through structural equation modelling. The statistical population included all secondary school principals in Isfahan, Iran (n = 323), of whom 175 were selected via stratified sampling method. The data were collected via interviews and a validated researcher-made self-development questionnaire with a reliability coefficient of 0.85. Moreover, Paterson’s (1989) standard job performance questionnaire was applied. The qualitative findings show 3 main categories with 16 sub-categories for the self-development variable and the quantitative findings indicate that school principals’ self-development correlates with their job performance (correlation coefficient = 0.68). The structural equations modeling of principals’ self-development and job performance with approved fit indices revealed that self-development affects job performance (impact coefficient = 0.749). The results of stepwise regression indicated that individual and organizational components can predict 40% of principal’s job performance. The present study shows that self-improvement through individual and organizational components affect the job performance of school principals. So school principals will definitely have better job performance if they can evaluate themselves, control their behaviors, gain self-awareness, and stay motivated by setting goals and planning.
