Place Guillaume II (French pronunciation: [plas ɡijom dø]) is a town square in Luxembourg City, in southern Luxembourg. The square is in the heart of Luxembourg's historic Ville Haute quarter. It is colloquially known as Knuedler, from the Luxembourgish language's word for "knot", referring to the knot in the belt worn by Franciscan friars.
The western half of the square is dominated by Luxembourg City Hall in the southwest, whilst the equestrian statue to former Grand Duke William II, after whom the square is named, is the prominent feature of the eastern half. Much of the square is ringed with trees, narrowing the open area (particularly around the statue).