The Manitoba Grain Growers' Association (MGGA) was a farmer's association that was active in Manitoba, Canada in the first two decades of the 20th century. It provided a voice for farmers in their struggle with grain dealers and the railways, and was influential in obtaining favorable legislation. The MGGA supported the Grain Growers' Grain Company, a cooperative of prairie farmers, and its organ the Grain Growers' Guide. At first it remained neutral politically, but in 1920 it restructured as the United Farmers of Manitoba in preparation for becoming a political party.