The leadership literature suggests that a servant leadership style can reduce negative employee outcomes, even in challenging work environments such as the educational sector, where teachers play a key role in social development. This research aimed to evaluate the effect of servant leadership on work happiness and organizational justice. An explanatory study was carried out including 210 men and women who declared that they perform teaching activities, aged between 21 and 68 years (M = 38.63, SD = 10.00). The data were collected using a self-report scale of servant leadership, work happiness and organizational justice, obtaining an adequate measurement model (α = between 0.902 and 0.959; CR = between 0.923 and 0.963; AVE = 0.604 and 0.631; VIF = between 1.880 and 2.727). The theoretical model was evaluated using the Partial Least-Squares PLS-SEM method. According to the results, the hypotheses were confirmed, demonstrating that there is a significant positive effect of servant leadership on work happiness (β = 0.69; p < 0.001) and organizational justice (β = 0.24; p < 0.001) and a positive effect of work happiness on organizational justice (β = 0.61; p < 0.001). This research provides valuable insight for educational leaders seeking to improve perceptions of happiness and justice in their organizations and promotes servant leadership to achieve this goal.