An online version of the face-to-face (F2F) Anatomy and Radiology Contouring (ARC) Bootcamp was held for radiation oncology (RO) residents. The course was designed along the analysis, design, development, implementation and evaluation (ADDIE) model and organized into 11 locked linearly and structured modules. An online manual was provided containing five learning modules for each anatomic site (head and neck, thorax, abdomen, male pelvis and female pelvis). The course's online radiology and contouring lectures were modeled after the F2F ARC Bootcamp lectures. Participants could discuss concepts with their peers in three discussion forums. The Bootcamp was launched on the Teachable course-building platform in November 2019. 27 of 140 enrollees completed all course requirements. Women comprised 37% of this group, and 52% were in medical physics residents or medical students rather than RO residents. Most participants said they were motivated to expand their subject knowledge/skills, specifically anatomy knowledge and contouring abilities. They cited course quality as it related to the design, material and instructors as a major strength of the Bootcamp. Participants also suggested more content would improve the course. "The online offering is more accessible to learners resulting in enrollments from a diverse cohort of participants, provides a self-paced, flexible learning environment and allows learners to assess their knowledge using integrated assessments," the authors conclude. They added that the Bootcamp will be continuously monitored via the integrated assessments and participants' feedback to make any necessary changes to fulfill learners' requirements.