Teacher professional learning plays a critical role in education reform by enabling teachers to refine their professional skills and keep up with changing content knowledge, pedagogy, and trends in schooling. This study examines how and under what conditions principal instructional leadership contributes to teachers' professional learning in mainland China. Data collected from 1194 teachers in 64 primary and middle schools in mainland China were analyzed using structural equation modeling and bootstrapping tests. The research tested a moderated mediation model of instructional leadership effects on teacher professional learning in which teacher self-efficacy was included as the mediator and power distance orientation of teachers as the moderator. The results reaffirmed the partial mediation model, finding significant direct and indirect effects of principal instructional leadership on teacher professional learning. Further model testing found that the individual power distance orientation of teachers acted as a significant moderator of principal instructional leadership effects on both teacher self-efficacy and professional learning. When teachers perceived lower power distance in relations with their principals, the effects of principal instructional leadership were stronger than for counterparts who perceived high power distance. Implications for understanding the contextualized nature of school leadership during an era of cultural change are discussed.