With nearly half of all new teachers leaving the classroom within 5 years, schools are faced with the challenge of retaining early-career teachers while simultaneously providing them with the support they need to develop into effective professionals. Mentoring novice teachers by pairing them with experienced teachers in schools is a widely adopted practice for addressing these needs; however, face-to-face mentoring is subject to challenges. A promising complement to face-to-face mentoring may be found in the innovative use of computer-mediated communications, such as online forums. In an effort to support, develop, and retain novice teachers, The College of William and Mary has partnered with the Center for Teacher Quality to create ENDAPT—Electronically Networking to Develop Accomplished Professional Teachers. ENDAPT is an asynchronous online forum that brings together novice teachers and teacher leaders in a virtual mentoring community. This article provides an overview of the program model and presents research findings from a study of participants’ postings using content analysis methodology to identify and describe the nature of professional conversations among mentors and novice teachers. Using grounded frameworks for mentoring conversations and for teacher competencies, the study evaluates the efficacy of online mentoring as a means of supporting and developing novice teachers.