Liam Ó Buachalla (1899 – 15 October 1970) was a Fianna Fáil politician from County Galway in Ireland. He was a Senator from 1939 to 1969, and was twice elected as Cathaoirleach of Seanad Éireann.
A Professor of Economics at University College Galway (UCG), Ó Buachalla was nominated by the Taoiseach Éamon de Valera to the 3rd Seanad in 1939, to fill the vacancy caused by the death of Colonel Maurice Moore. He was re-appointed to the 4th Seanad and to the 5th. After Fianna Fáil lost power at the 1948 general election, the new Fine Gael Taoiseach was unlikely to reappoint him, and he was elected to the 6th Seanad on the Cultural and Educational Panel. He was re-elected five times, until he stood down at the 1969 Seanad election.
He was Cathaoirleach (chairman) of the Seanad from 1951 to 1954, and from 1957 to 1969, and also served as Leas-Chathaoirleach (deputy chairman) from 1954 to 1957.
His wife Máire Ní Scolaí (died 1985) was a notable singer of songs in Irish and also an actress.