Barlings Eau is a small river near Barlings, Lincolnshire, England. It is a tributary of the River Witham, joining it near Short Ferry. It acts as the central spine for a number of other small rivers, which drain the low-lying land to either side. Most of its course is within the area managed by the Witham Third District IDB, an Internal Drainage Board responsible for land drainage. One of their pumping stations is on the banks of the river.