Understanding how ecosystem services interact to support crop yield is essential for achieving food security. Here we evaluate the interactions among biotic pest regulation, pollination, and nutrient cycling. We found only 16 studies providing 20 analyses of two-way interactions. These studies show that multiple services limit crop yield simultaneously. Complementary effects (no interactions) between ecosystem services were the most common, followed by synergistic effects (positive interactions), while evidence for negative interactions was weak. Most studies evaluated two levels of service delivery, thus did not quantify the functional response of crop yield. Although this function is expected to be non-linear, most studies assume linear relations. We conclude that the lack of evidence for negative interactions has important implications for agricultural management.