De Rat (English: The Rat) is a smock mill in IJlst, Friesland, Netherlands, which was originally built in the seventeenth century at Zaanstreek, North Holland. In 1828 it was moved to IJlst, where it worked using wind power until 1920 and then by electric motor until 1950. The mill was bought by the town of IJlst in 1956 and restored in the mid-1960s. Further restoration in the mid-1970s returned the mill to full working order. De Rat is working for trade and is used as a training mill. The mill is listed as a Rijksmonument (No. 39880).