William Isaac Furness (8 June 1909 – 29 August 1980) was an English professional footballer who played as an inside forward for Leeds United and Norwich City in the 1930s, making one appearance for England in 1933.
Furness was born in Washington, County Durham and played his early football for Usworth Colliery from where he was signed by Leeds United in August 1928 for a fee of £50.
Furness's form was to be rewarded with his solitary England cap, when he was selected, along with his Leeds teammate Wilf Copping, for the first-ever match against Italy on 13 May 1933.
In a memorable match against Leicester City on 7 April 1934 Furness, Harry Duggan, Joe Firth and Johnny Mahon each scored twice in an 8–0 victory – this remains Leeds' best ever League win.
Things improved slightly for Leeds in 1935–36 with an eleventh-place finish with Furness contributing seven goals (including a penalty against Arsenal in the final match of the season) with George Brown top scorer on 20.