Kirkby Underwood is a village and civil parish in the South Kesteven district of Lincolnshire, England. It is situated 4 miles (6 km) north from Bourne and 1 mile (1.6 km) west from the main A15 trunk road. To the east is Rippingale and the Fens. Directly to the south is the hamlet of Stainfield, and to the west, Hawthorpe.