School counselors have voiced a desire for more training and professional development, specifically in the implementation of comprehensive school counseling programs, college and career advisement, addressing mental health needs, and crisis response and management. School counseling professional competencies and code of ethics describe the need for and obligation to professional development. While opportunities for professional development are likely available, there is little literature describing school counselors involvement in professional development. The purpose of this study is to generate a new theory, grounded in the collected qualitative data, of how school counselors make decisions regarding professional development. The intent of this study is to use the resulting theory to offer insight, enhance understanding, and contribute to the literature regarding school counselors professional development decision making. Therefore, the research question guiding this endeavor was, What factors explain school counselors decision making regarding professional development? Semi-structured interviews were conducted and data was collected and analyzed using Constructivist Grounded Theory methods (Charmaz, 2014). Four themes emerged from data analysis and were used to create a three-circle Venn diagram which visually represents the School Counseling Professional Development Decision Making Model. The four themes were (a) Lifelong Learner Foundation, (b) Logistics, (c) Interest, and (d) Impact on K-12 School Counseling Program. Sub-factors within each theme provided further explanation on the decision-making process of school counselors regarding professional development. The first theme represented how enrollment in a Transforming School Counseling Initiative school counseling program laid a foundation of lifelong learning for school counselors and thus influenced the value placed on professional development. It is with a foundation in lifelong learning and at the intersection of the three remaining themes that professional development decisions are made. The findings of this study were presented through the lens of three developmental perspectives: (a) role identity theories, (b) Supers Life-Span Life-Space theory of career development, and (c) Ronnestad and Skovholts Model of Therapist Development.