Lagging student performance in the Sultanate of Oman has, in recent years, led the Ministry of Education to target teachers' professional learning as a key strategic pillar in its efforts to reform the education system. While international evidence finds principal leadership can make a meaningful difference in teacher engagement in professional learning, this has yet to be studied in Arab societies. The current study collected data from 887 teachers in 78 Omani middle schools with the aim of understanding if and how their principals' learning-centered leadership influences teacher agency, teacher trust and teacher professional learning. Factor analysis, structural equation modelling, and bootstrapping were used to explore both partial and full mediation models of these relationships. Results validated a partial mediation model in which learning-centered leadership had moderate direct and indirect effects on teacher professional learning. The validated model also highlights the important role that principals can play in creating a climate of trust where teachers believe that investing their time and effort in professional learning will be beneficial for themselves and their schools. The results from Oman are compared with findings from other Asian societies and implications discussed.