Objective: To determine perceived barriers and facilitators to effective mentoring for early career rheumatology investigators and to develop a framework for an inter-institutional mentoring program. Methods: Focus groups or interviews with rheumatology fellows, junior faculty, and mentors were conducted, audiorecorded, and transcribed. Content analysis was performed using NVivo software. Themes were grouped into categories (e.g., mentor-mentee relationship, barriers, and facilitators of a productive relationship). Rheumatology fellows and early career investigators were also surveyed nationwide to identify specific needs to be addressed through an inter-institutional mentoring program. Results: Twenty-five individuals participated in focus groups or interviews. Attributes of the ideal mentee-mentor relationship included communication, accessibility, regular meetings, shared interests, aligned goals, and mutual respect. The mentee should be proactive, efficient, engaged, committed, focused, accountable, and respectful of the mentor's time. The mentor should support/promote the mentee, shape the mentee's goals and career plan, address day-to-day questions, provide critical feedback, be available, and have team leadership skills. Barriers included difficulty with career path navigation, gaining independence, internal competition, authorship, time demands, funding, and work-life balance. Facilitators of a successful relationship included having a diverse network of mentors filling different roles, mentor-mentee relationship management, and confidence. Among 187 survey respondents, the primary uses of an inter-institutional mentoring program were career development planning and oversight, goal-setting, and networking. Conclusions: In this mixed-methods study, tangible factors for optimizing the mentor-mentee relationship were identified and will inform the development of an adult rheumatology inter-institutional mentoring program.