This project centers on the creation and validation of a theoretically-grounded and empirically-derived Framework for professional growth and learning within the informal STEM learning (ISL) field. The Framework will be useful to ISL practitioners at any stage of their education or career by laying out the skills, knowledge, and dispositions necessary to guide professional growth. The project addresses two current and pressing issues: (1) Ensuring that professionals working in science center-type settings have the necessary knowledge and skills to apply the substantial and growing evidence base in ISL, and (2) Understanding and supporting the needs of the full range of ISL professionals during their basic education and at particular points throughout their careers.