This study explored an emerging practice, online video coaching, which builds on the affordances of digital technology to allow coaches to work with geographically distant teachers. Content-focused mathematics coaching has proven successful in a face-to-face environment because of its personalized nature, long-term sustainability, and the opportunity to address concerns and challenges within teachers' daily mathematics instruction. However, this model is expensive for school districts to maintain and is limited to the expertise of local mathematics coaches. Current technology has now made coaches accessible to schools and classroom teachers, regardless of location. This study followed nine mathematics coaches for three years in an online content-focused coaching project aimed at middle school mathematics teachers in rural contexts. The coaching work included cycles of co-planning instruction, analysis of videorecorded instruction, and post-instruction conferences to reflect on planning and instruction. The data in this study included interviews with each coach in the third year of the project and background surveys. Current research on content-focused coaching has yet to identify specific high-leverage coaching practices that support mathematics instruction. This study analyzed the coaches' descriptions of their experiences with online coaching to identify specific practices and how they believed these practices would support teacher learning. The analysis of this data revealed nine coaching practices; getting familiar with the lesson materials, creating a plan to guide the pre-lesson conversation, developing goals for lesson enactment, anticipating student thinking, rehearsing teachers' enactment of the lesson, watching the lesson video, writing annotations, creating a plan for the post-lesson discussion, and using evidence to focus on student learning and instructional practice goals. The descriptions of these coaching practices revealed how the coaches adapted to the online environment, how student learning goals were the foundation of coaching discussions, and how coaches balance their dual roles as a content expert and a thinking partner to support teacher learning in their coaching interactions. The implications of this study contribute to the current knowledge of high-leverage coaching practices and ways content-focused coaching can support teacher learning. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]