Methods and materials in English Language Teaching (ELT) are influenced by the unique socio-cultural contexts of instruction. Nonetheless, English as a Foreign Language (EFL) teaching practices in the Arabian Gulf tend to adopt a one-size-fits-all approach when it comes to teaching methods and pedagogical approaches. This study investigates the influence of the Cambridge English Teacher (CET) professional development program on the classroom practices of EFL instructors in the Arabian Gulf and its role in facilitating the contextualization of teaching in alignment with Saudi cultural norms. The study involved 120 Saudi EFL university teachers as participants. Employing a convergent parallel design that incorporated a survey questionnaire and semi-structured interviews, the results demonstrated that the CET program empowered participants to contextualize their teaching methods and adapt their classroom delivery to the local teaching environment. Specifically, the findings revealed that participants perceived their learning experience in the CET program in four distinct dimensions: contextualizing teaching methods, localizing Communicative Language Teaching (CLT) principles, diversifying teaching methodologies and materials, and comprehending context-specific classroom management strategies. Moreover, the study highlighted the significant impact of contextually tailored in-service professional development programs in the process of "glocalizing" teaching methods. In conclusion, the research findings carry implications for EFL educators, professional development initiatives, and provide valuable directions for future research endeavors.