Churches have been a popular site for the implementation of health promotion interventions. Although the efficacy of church-based health programs have been established, it is unknown which aspects of church-based health promotion drive health behavior change. Process evaluation is a way to increase our understanding of key components of church-based health promotion and to move the field forward. Thus, a systematic review of the utilization of process evaluation in church-based health programs was conducted. Articles from 1990 to 2008 were screened for eligibility, resulting in the analysis of 67 articles. The majority of church-based health programs assessed recruitment (88.1%) and reach (80.6%). About 28.4% assessed dose delivered, and 27.3% measured dose received. Context and fidelity was assessed by 34.3% and 20.9%, respectively, of church-based interventions. Approximately 9% of church-based programs measured fidelity. On average, only three of seven possible components of process evaluation were measured among the studies reviewed. The number of process evaluation components assessed did not differ by program feature (e.g., target population, target health condition, program objective, etc.). Consistency in the conceptualization and measurement of process evaluation may facilitate the implementation of a comprehensive process evaluation effort in church-based and other health promotion interventions.