Purpose: The role of leadership through senior management teams (SMT) has received increasing attention over the past several decades. Such leadership requires principals to play a key role in promoting SMT effectiveness. Therefore, according to the input-mediator-outcome model (Ilgen et al., 2005), this study's purpose is to investigate the mediating role of school SMT learning in the relationship between principal systems thinking (PST) and SMT effectiveness after accounting for students' socioeconomic backgrounds and SMT members' tenure. Design/methodology/approach: A three-source survey design with self-reported and non-self-reported data was used, from a sample of 282 participants from 71 elementary schools in Israel. The sample included principals and SMTs. Data were aggregated at the school level of analysis. Findings: The results from structural equation modeling and bootstrapping analysis indicated that SMT learning fully mediates the relationship between PST and SMT effectiveness, irrespective of the students' socioeconomic backgrounds. Originality/value: This study provides important insights into the role of SMT learning as a mediator in the relationship between PST and SMT effectiveness. In addition, the study responds to the call of previous studies to examine the effects of PST on characteristics and outcomes at the group level. Moreover, the proposed integrative model highlights the importance of SMT learning and suggests new ways to encourage it.