The Uzbekistan Education for Excellence Program (the Program), funded by the United States Agency for International Development, designed the teacher professional development (TPD) effectiveness study to assess the effectiveness of the Program’s TPD approach in terms of teachers’ satisfaction of learning events, their acquisition of knowledge and skills, their shift in self-efficacy, possible changes in teacher beliefs about new teaching approaches, and to what extent teachers received the necessary support at the administrative and school levels. The Program also used quality assurance data derived from the study to minimize dilution effects of the cascade approach and to inform and adapt the ongoing TPD activities as needed.