Agriculture on the precontact Great Plains describes the agriculture of the Indigenous peoples of the Great Plains of the United States and southern Canada in the Pre-Columbian era and before extensive contact with European explorers, which in most areas occurred by 1750. The principal crops grown by Indian farmers were maize (corn), beans, and squash, including pumpkins. Sunflowers, goosefoot, tobacco, gourds, and plums, were also grown.

The Three Sisters are the three main agricultural crops of various indigenous peoples of Central and North America: squash, maize ("corn"), and climbing beans. In a technique known as companion planting, the maize and beans are often planted together in mounds formed by hilling soil around the base of the plants each year; squash is typically planted between the mounds. The cornstalk serves as a trellis for climbing beans, the beans fix nitrogen in their root nodules and stabilize the maize in high winds, and the wide leaves of the squash plant shade the ground, keeping the soil moist and helping prevent the establishment of weeds.