This quantitative study aims to examine the relationships between enabling school structure, academic optimism and altruistic behaviours as well as to find out whether altruistic behaviours serve as a mediator between enabling school structure and academic optimism. A scale was applied to teachers from primary- schools in Turkey via random sampling. There were 707 teachers participating in this study. Three existing scales, which are enabling school structure, academic optimism, and teachers' altruistic behaviours scales, were used to collect data from teachers. Descriptive statistics and bivariate correlations were calculated in the study to investigate correlations among all the variables and reliabilities of the measures. Structural Equation Modelling investigated the effects of Enabling School Structure on School Academic Optimism through Teachers' Altruistic Behaviours. The results confirmed a positive relationship between all variables of the study. The findings also revealed the mediator effect of TAB on the relationship between ESS and SAO. Finally, some recommendations were given based on results.