The destruction of ecosystems for vegetable oil production represents a major cause of global biodiversity loss and greenhouse gas emissions 1. Over the last two decades, oil palm, in particular, has caused societal concern due to its high impacts on biodiverse and carbon-dense tropical rainforests 2–8, leading to calls to source vegetable oils from alternative oil-producing crops. However, given the high yields of oil palm, how does that damage compare with other oil crops that require more land? Here, we estimate the carbon and biodiversity footprints, per unit of oil produced, of the world’s five major vegetable oil crops. We find that oil palm has the lowest carbon loss and species richness loss per-tonne-oil, but has a larger impact on range-restricted species than sunflower and rapeseed. We go on to identify global areas for oil crop expansion that will minimise future carbon and biodiversity impacts, and argue that closing current yield gaps and optimising the location of future growing areas will be much more effective at reducing future environmental impacts of global vegetable oil production than substituting any one crop for another.