In the realm of middle level education, advocacy is an integral aspect of school culture and community. Advocacy helps to foster a school environment characterized by a sense of respect and value for young adolescents and should take up an awareness of the social and cognitive characteristics of young adolescents. Advocacy competency is also a necessary teacher disposition to foster socially just and successful middle school cultures and climates. We conducted a systematic review of the literature guided by the following driving question: What does the research say about middle level teacher development and advocacy? Our review yielded 38 relevant sources and key thematic ideas across four thematic categories. We anticipate this review of the literature will be of interest to and inform middle level educators and researchers around equity- and justice-oriented middle level teacher development.