A community of practice (CoP) is a group of people who share a concern or a passion for something they do and learn how to do it as they interact regularly. Higher education leaders are attracted to CoPs because they are a peer-based model of learning with colleagues, which works well for professionals such as faculty. These authors identified four long-standing CoPs and studied them with the goal of understanding how they are designed to achieve their goals; benefits of participation in them; and how they form, grow, and are sustained. This paper focuses on the results from the third emphasis related to these CoPs' lifecycle and is framed by the literature on CoPs related to the five stage lifecycle model (Wenger, McDermott, & Snyder, 2002). The authors focus specifically on the third stage--called maturing--in which they identify some substantial variations in the higher education CoPs aimed at broadening their reach and recruiting new members. This article focuses on the research question: How do STEM reform communities grow and increase their impact on STEM reform over time? The study helps CoPs within higher education as well as in other sectors to identify practical strategies and challenges related to adopting these recruitment and growth strategies.