This study aims to examine the impact of self-esteem on teacher leadership beliefs in Türkiye through both correlational and experimental analyses since self-esteem is considered to be a crucial antecedent of leadership. The author conducts three separate studies with a sample size of 808. The first study (n = 237) uses correlational analyses (Spearman). The second study (n = 222) adopts a scenario-based, within-participants experimental design where the self-esteem level of teachers is manipulated. A paired t-test was used to analyze the data. The third study (n=349) employs a between-participants experimental design. ANOVA test was conducted to analyze the data. The correlational analysis of the first study found a positive relationship between self-esteem and teacher leadership (rho =0.35, p < 0.001). The second study revealed that participants perceived teachers with high self-esteem to be more likely to exercise leadership, t[subscript (221)] = 1.97, p < 0.01. The third study found that teachers who were primed to have high self-esteem were more likely to adopt leadership beliefs, F[subscript (2, 348)] = 3.91, p = 0.02. The result experimentally demonstrated that self-esteem is an important antecedent of teacher leadership. This study contributes to the literature on teacher leadership by providing a causal link between self-esteem and teacher leadership.