John II, Count of Hainaut

John II of Avesnes (1247–1304), son of Count John I of Hainaut and Adelaide of Holland, became count of Hainaut in 1280 on his grandmother Margaret's death and inherited Holland and Zeeland in 1299, uniting the three counties. Backed by France, he fought Count Guy of Flanders for Imperial Flanders.

His eldest son was killed fighting for France at the Golden Spurs in 1302. John's enemies overran much of Holland and Zeeland, and Guy of Namur defeated his son William at Duiveland, until the Franco-Holland fleet defeated Guy off Zierikzee in 1304. He died later that year, succeeded by his son William I.