This article reports on the development and evaluation of a massive open online course (MOOC) that provides instruction on best practices in research data management (RDM). The course was developed in response to the growing need for data management professional development for LIS professionals and to promote data management to researchers. In just 18 months of the course launch, the course reached more than 1,000 people from across the world and was effective in building student competency in RDM. The success of this course illustrates the value and utility of free online professional development as a tool for both library and research staff.