Insect pests are a major challenge to smallholder crop production in sub-Saharan Africa, where access to synthetic pesticides, which are linked to environmental and health risks, is often limited. Biological control interventions could offer a sustainable solution, yet an understanding of their effectiveness is lacking. We conducted a meta-analysis of 5 commonly-used biocontrol interventions to quantify i) the magnitude of their effects when compared with no control and with synthetic pesticides, and ii) how effectiveness is determined by landscape composition. Overall, compared to no control, biocontrol interventions reduced pest abundance by 63%, crop damage by over 50%, and increased crop yield by over 60%. Compared to synthetic pesticides, biocontrol produced comparable yields, and natural enemy abundance was 43% greater. Our results suggest that biocontrol represents an effective intervention for farmers who do not have access to pesticides, while it can maintain yields without associated negative pesticide effects. However, the potential for biocontrol to be affected by landscape composition is a critical knowledge gap in sub-Saharan Africa.