Data were collected from 32 teachers using mixed methods to investigate their perceptions of the value of online professional development (PD) offered through a school-community partnership with National Aeronautics and Space Administration (NASA). The partnership between multiple school districts nationwide and NASA provided teachers with an online Science, Technology, Engineering and Mathematics (STEM) PD course called MicroGX. Data from this study provide evidence that teachers perceived MicroGX as a positive PD experience. Teachers indicated that they would recommend this PD to other teachers, and overall were satisfied with interaction with others, resources, support, content, and content delivery. Effective PD components include building teachers’ content knowledge, impacting students’ learning, increasing teaching resources, and providing support for participation in PD.