While formal early career mentoring is considered significant for faculty success, few universities have instituted programmatic mid-career mentoring. We review the reasons mid-career mentoring is important especially for under-represented (URM) faculty and consider the ways the entrenched model of one-on-one mentoring can fail URM faculty. We advocate for a feminist-inspired peer mentoring approach using a Community of Practice model that supports mentoring as advocacy. We then describe how our own mid-career mentoring program enacts this approach and offer lessons learned that include the need to make a cost-analysis case.