While there has been a remarkable interest to make computer science a core K-12 academic subject in the United States, there is a shortage of K-12 computer science teachers to successfully implement computer sciences courses in schools. In order to enhance computer science teacher capacity, training programs have been offered through teacher professional development. In this study, the main goal was to systematically review the studies regarding computer science professional development to understand the scope, context, and effectiveness of these programs in the past decade (2004-2014). Based on 21 journal articles and conference proceedings, this study explored: (1) Type of professional development organization and source of funding, (2) professional development structure and participants, (3) goal of professional development and type of evaluation used, (4) specific computer science concepts and training tools used, (5) and their effectiveness to improve teacher practice and student learning.