With the recent upsurge in the development, use, and adoption of free/libre open source software (FLOSS) across all sectors of business, it is critical that graduates of computing degree programs gain an understanding of FLOSS development tools, processes, and culture. However, many faculty members are not fluent in FLOSS development and have little experience in teaching FLOSS. This paper reports on a faculty development program designed to bring instructors up to speed on how to support student learning within FLOSS projects. The paper dis-cusses the challenges to FLOSS education from the instructor’s perspective, describes the Professors’ Open Source Software Experience (POSSE) workshop, and presents the results of a study into the impact of POSSE on instructors based on semi-structured interviews. This work is part of a larger study into instructor experiences when incorporating Humanitarian Free Open Source Software (HFOSS) into their curriculum.