Bird's-foot trefoil is native to temperate Eurasia and North Africa, where it grows in grassland and on sandy soils and tolerates grazing. Bumblebees are its main visitors, along with honey bees and mason bees, and several European butterflies use it as a caterpillar food plant.
It was brought to North America for livestock forage and erosion control and planted in pastures and along roadsides. It now escapes into natural areas and is considered invasive in many parts of North America, where it forms dense mats that shade out native plants. The common name refers to the pod shape and the three prominent leaflets.