William Llewellyn Dyer (11 September 1883 – 1936) was an English businessman and a professional footballer who played as a striker for Athletic Club. He was one of the first pioneers of football in the Basque Country, standing out as a great striker for some of the earliest Basque clubs in existence such as Bilbao FC, Club Bizcaya, and Athletic Club, winning three back-to-back Spanish Cups with the latter two between 1902 and 1904, and being the joint top scorer in the 1902 Copa de la Coronación with 5 goals.