A self-cleaning gauge wheel assembly having a gauge wheel mounted for rotation on an agricultural planter and adjustable to set the depth of the planting. A pulley having a diameter at least 1/7th and less of the diameter of the gauge wheel is journaled about an axis spaced from and behind and elevated from the gauge wheel. An endless belt is provided around the gauge wheel and the pulley in tension so that movement of the planter, and associated rotation of the gauge wheel causes the pulley to accelerate any accumulated moist soil and expel it from the belt to provide a self-cleaning feature.