The objective of this study was to conduct a systematic review of the literature and examine the effectiveness, optimal circumstances, and best practices for strengthening linkages between family planning and HIV interventions. Researchers used a systematic review of peer-reviewed articles and unpublished program reports ('promising practices') evaluating interventions linking family planning and HIV services. Most studies reported generally positive or mixed results for key outcomes; no negative results were reported. Interventions linking family planning and HIV services were generally considered feasible and effective, though overall evaluation rigor was low.