Instructional coaching or mentoring, as a form of professional development for teachers, has gained importance as educational policy has called for the implementation of research-validated instructional practices by highly qualified teachers. Technology-mediated mentoring has strong potential for overcoming barriers of accessibility and cost-effectiveness associated with traditional on-site mentoring. The purpose of this article is to synthesize existing peer-reviewed empirical studies on technology-mediated mentoring for inservice teachers. Three mediums for technology-based mentoring were explored: technology-enhanced professional development coupled with access to a mentor, electronic mail, and online discussion forums. The synthesized studies primarily incorporated mixed-methodologies or were qualitative. Results suggest that, although usage of some technology-based mentoring implementations was low or variable, those who accessed the resources generally reported having a positive experience, reporting shifts in their attitudes towards instruction and changes in instructional practices; however, few studies substantiated teacher self-reported improvement in knowledge and practice through direct observation. While existing research is both informative and encouraging, more rigorous qualitative and quantitative research, particularly quasi-experimental and experimental studies, is needed. As no located studies addressed the impact of the technology-based mentoring of teachers on the outcomes of students, particular attention should be paid to this significant outcome variable in future research. (Contains 1 table.)