Work engagement among teachers is a significant concern in education. This study examined the adaptability behavior as a mediator on the relationship between instructional leadership and work engagement. Through predictive research design, data surveyed from 231 public elementary school teachers, selected through simple random sampling, were analyzed using mediation analysis. Results revealed that adaptability behavior partially but significantly mediates the relationship between instructional leadership and work engagement, thereby partly affirming Social Cognitive Theory. Future research may examine additional variables and use qualitative approaches to explain the remaining variance in the mediation.