Maize (Zea mays L.) is important in semiarid West Africa where the increase in demand exceeds the increase in production. Yield is often constrained by inadequate nutrient availability even though the occurrence of soil water deficits may overall be more constraining. Research was conducted in semiarid Mali and Niger to determine the yield and profit responses of maize sole crop (MzSC) to N, P, and K and to develop a procedure for determining maize-groundnut (Arachis hypogaea L.) intercrop (MzGnI) nutrient response functions from MzSC functions. Trials were conducted in 2014 and 2015 at five locations spanning 14 degrees of longitude and two degrees of latitude. Mean MzSC grain yield increase due to 50 kg ha(-1) N was 0.69 Mg ha(-1) in Mali and 0.42 Mg ha(-1) in Niger, and due to 10 kg ha(-1) P was 0.14 Mg ha(-1) in Niger with inconsistent P effects in Mali. Responses to K were negligible. Productivity and profit potential with N application was more with MzGnI compared with MzSC, but profit potential for applied P and K were not improved with MzGnI. Considering the fodder value of stover added to production value but did not have much effect on profits from fertilizer use. The procedure for determining MzGnI nutrient response functions by adapting MzSC functions was developed, providing a means to improve fertilizer use efficiency for MzGnI. Productivity and returns to applied N, on a maize grain value equivalent, are greater with MzGnI compared to MzSC.