This paper outlines an approach to teachers' professional development (PD) that originates in Vygotsky's sociocultural theory (SCT), arguing that what Vygotsky claimed about students' learning in the school setting is applicable to the teachers and that the developmental theories of Vygotsky resting on the notions of social origin of mental functions, unity of behavior and consciousness, mediation, and psychological systems can help more vividly understand the professional growth of teachers in their work places. The paper discusses how the seven influential models of professional development mostly coded in the literature namely: "mentoring", "observation/assessment", "scaffolding", "inquiry/action research", "individually guided activities", "study groups", and "involvement in a development process" can be best grounded in Vygotsky's theoretical framework. It is claimed that the commonality that interweaves the aforementioned models is Vygotsky's concept of "social mediation". Finally, the paper concludes with a discussion of the various implications of the proposed approach for designing and implementing teacher professional development by linking the developmental aspects of professional development and core tenets of Vygotsky's developmental theories.