William "Bill" Loughnane (5 August 1915 – 18 October 1982) was an Irish Fianna Fáil politician.
A medical doctor by profession, he was first elected to Dáil Éireann as a Fianna Fáil Teachta Dála (TD) for the Clare–Galway South constituency at the 1969 general election. He was re-elected at the 1973 general election for the same constituency. He was elected for the Galway West constituency at the 1977 general election, and was elected for the Clare constituency at the 1981 and February 1982 general elections. He died in October 1982 shortly before the November 1982 general election.
He was a noted Republican backbencher within Fianna Fáil. He and Síle de Valera were highly critical of the then Taoiseach Jack Lynch , criticism which precipitated Lynch's resignation in 1979. He was also a supporter of the Anti H-Block movement.