Gimme 5: A Fresh Nutrition Concept for Students (Gimme 5) was a 4-year intervention targeting increased fruit and vegetable consumption by high school students. Twelve schools were randomized to intervention or control conditions. The cohort (2,213 students; 56% female, 84% Euro-American) were followed from 9th to 12th grade. Interventions were composed of a school-based media campaign, classroom workshops, school meal modification, and parental involvement. For each of the four Gimme 5 intervention components, process evaluation measures were developed to assess program dose, penetration, and utilization, as well as external competing factors. Process evaluation results are presented to illustrate the various functions of process evaluation data. These include, but are not limited to, describing program implementation, quality control and monitoring, and explaining study outcomes. The implementation of process evaluation systems to complement the outcome measures in a high school-based intervention provides useful strategies for a more comprehensive approach to program evaluation.