The Right Honourable Dafydd Wigley (born April 1, 1943) is a Welsh politician. He served as Plaid Cymru member of Parliament for Caernarfon until 2001, and was leader of the party from 1991 to 2000.

Wigley was born in Derby, England, but attended Caernarfon grammar school before going on to the University of Manchester and training as an accountant. He was employed by Hoover as a financial controller before entering parliament.

He married the international harpist Elinor Bennett . The couple had four children, but twin sons died of a genetic illness. His sons' condition influenced the direction of his career, and he took a strong interest in the affairs of disabled people, being vice-chair of the Parliamentary all-party disablement group, vice-president of Disability Wales, vice-president of Mencap (Wales), former president of the Spastics' Society of Wales and sponsor of the Disabled Persons Act in 1981.

In 1974 he became one of Plaid Cymru's first three MPs to be elected at a General Election, and first became the party's president in 1981. Unusually, his personal politics were right-wing. In 1984 he resigned from the presidency because of his children's health, but returned to the job in 1991 after the resignation of Dafydd Elis Thomas.

In 1999 Wigley became a member of the National Assembly for Wales, and led the Plaid Cymru opposition to Labour. He was repeatedly nominated by the Welsh public as the most popular political party leader, before his resignation from the leadership on medical advice in 2000. In 2003 he became Pro-Chancellor of the University of Wales.