Waldo (Goronwy) Williams (30th September 1904 – 20th May 1971) was one of the leading Welsh language poets of the twentieth century. He was also a notable pacifist, anti-war campaigner, and Welsh nationalist

Williams was born in Haverfordwest, Pembrokeshire. His father, a primary school teacher from Pembrokeshire, spoke Welsh and his mother spoke English. In his early years he himself spoke only English.

In 1911 his father was appointed headteacher of the primary school at Mynachlog-ddu, Pembrokeshire and it was there that Waldo Williams learnt to speak Welsh. In 1915 Williams's father moved to be headteacher of Brynconin School, the primary school at Llandysilio, Pembrokeshire.

After attending the Grammar School at Narberth, Pembrokeshire he studied at the University College of Wales, Aberystwyth where he graduated in English in 1926. Afterwards he trained as a teacher and worked in various schools in Pembrokeshire, the rest of Wales and England. He also taught night classes organised by the Department of Extre-Mural Studies, University College of Wales, Aberystwyth.

Williams married Linda Llewellyn in the Narberth district of Pembrokeshire in the second quarter of 1941, but his wife died in 1943, and he did not remarry.

In 1944 he moves to teach at Kimbolton, Huntingdonshire and after a year moves to Lyneham Wiltshire where he taught at Lyneham School between 1946-1949. Maude E.I. Webb who was Headteacher at the time of his teaching profession. She was a talented and gifted musician and as well as being organist at Lyneham Church took much part in musical activities in Calne. Maude Webb was headteacher at Lyneham School from 1935 - 1956.

Waldo Williams wrote some  poetry while in England. Nearly all his poetry is in Welsh although one volume is translated by another poet Tony Conran "The Peacemakers".

During the Korean War he refused to pay his income tax on pacifist grounds. He continued his protest until the ending of compulsory military service in 1963. During his campaigning he was sent to prison.

He stood as a parliamentary candidate for Plaid Cymru in the Pembrokeshire constituency at the 1959 General Election when he won 4.32% (2.253) of the votes.

He died in 1971 at St. Thomas's Hospital, Haverfordwest, Pembrokeshire and is buried at Blaenconin Chapel burial ground in Llandysilio.