Purpose: To describe the initial steps in the development of a family-completed, modified version of the Gross Motor Function Measure (GMFM-88) to report gross motor function of young people with cerebral palsy in their natural environments. Methods: Development of the Gross Motor Function – Family Report (GMF-FR) was based on expert opinion involving 13 experienced clinicians and researchers, in four steps: (1) item identification to target items that reflect functional gross motor performance; (2) item selection; (3) critical analysis of the items; and (4) item and scoring modification. Results: Several modifications to existing items and scoring were made, including wording changes to optimize ease of families’ understanding, the addition of photographs to illustrate all items, changes to the items to enable use of furniture instead of specialized equipment, and modifications to scoring criteria to ensure a focus on functional motor skills. Ultimately, 30 items were selected, and specific testing/scoring instructions were created for each item. Conclusions: GMF-FR is a new family-report tool, based on the GMFM-88. When validated, it can be used as a telehealth outcome measure to capture family-reported functional motor skill performance in home and community environments.