A rushlight is a type of candle or miniature torch formed by soaking the dried pith of the rush plant in fat or grease. For several centuries, rushlights were a common source of artificial light for poor people throughout the British Isles. They were extremely inexpensive to make. English essayist William Cobbett wrote, "This rushlight cost almost nothing to produce and was believed to give a better light than some poorly dipped candles."

One of the earliest printed descriptions of rushlights was written by English antiquary John Aubrey in 1673. Rev. Gilbert White gave a detailed description of rushlight making in The Natural History and Antiquities of Selborne, Letter XXVI (1789). Rushlights were still used in rural England to the end of the 19th century, and they had a temporary revival during World War II. In parts of Wales the use of rushlights continued into the middle of the 20th century.

It is not clear whether rushlights were ever popular in the United States and Canada. Antique rushlight holders are occasionally found in North America, but most were probably imported from England; "none are known to bear the mark of an American smith." In New England, "rushlights were used little if at all in colonial days."

Rushlights should not be confused with rush-candles. A rush-candle is an ordinary candle (a block or cylinder of tallow or wax) that uses a piece of rush as a wick. Rushlights, by contrast, are strips of plant fibre impregnated with tallow or grease. The wick is not separate from the fuel in a rushlight.