Sheelagh Mary Murnaghan (26 May 1924 — 14 September 1993) was an Ulster Liberal Party Member of Parliament (MP) in the House of Commons of Northern Ireland at Stormont.
Born into a Roman Catholic family in Dublin, the granddaughter of George Murnaghan, a Nationalist MP, she grew up in Omagh before studying law at Queen's University, Belfast, graduating in 1947. Whilst at Queen's she became the first female president of the Literary and Scientific Society (the Literific), the university debating society. She qualified as a barrister and played for the Irish national women's hockey team.
Murnaghan joined the Ulster Liberal Association in 1959, and unsuccessfully contested South Belfast in the British general election that year. In 1961, she won a by-election for Queens University Belfast and became the only Liberal member ever to sit in the Northern Ireland House of Commons.
While an MP, Murnaghan campaigned to abolish the death penalty and for a bill of human rights. When her seat was abolished, she failed to win North Down at the 1969 Northern Ireland general election, and was also unsuccessful in Belfast South at the Northern Ireland Assembly election, 1973. During the 1970s, she sat on various quangos, including the Industrial Relations Tribunal and the Equal Opportunities Commission. She continued to practice at the Bar, specialising in harassment cases.
From 1969 to 1972 she served on the first Northern Ireland Community Relations Commission and when Direct Rule was introduced, on Whitelaw's Advisory Commission. Later she chaired National Insurance and Industrial Relations Tribunals.
She died in 1993, aged 69, from undisclosed causes.