Intercropping maize with forage legumes can benefit Ethiopian smallholder farmers by providing cheap nitrogen and valuable livestock feed. We measured N₂O emissions and maize yields and found that high legume biomasses may enhance N₂O emissions per unit of harvested maize but that, after mulching, legume N can partly replace expensive mineral N. Thus, legume intercropping can be a valid strategy in the framework of climate-smart agriculture in sub-Saharan Africa.