Grandparents University ® (GPU) is a 2-day campus-based nutrition education program for grandparents and grandchildren based on constructs from Social Cognitive Theory and the Theory of Planned Behavior. This article describes how program theory was used to develop a working model, design activities, and select outcome measures of a 2-day nutrition program at GPU 2010 that fostered behavioral intention among intergenerational participants to eat more fruits and vegetables and become more physically active.