Deirdre Murphy (born 1953) is an Irish judge who has been a Judge of the High Court since April 2014.
She was educated at St Patrick's College, Maynooth and Trinity College Dublin. She was the winner of the Irish Times Debate in 1976. She attended the King's Inns and became a barrister in 1979. She became a senior counsel in 1999.
Her practice at the bar included acting for the defence and prosecuting on behalf of the Director of Public Prosecutions in criminal trials. She also practiced in the areas of constitutional law and judicial review. She represented the applicant in C(C) v Ireland who was successful in the Supreme Court in declaring part of the Criminal Law Amendment Act 1935 unconstitutional. The Act created strict liability with no defence of honest mistake to unlawful carnal knowledge. The outcome of the case led to the immediate introduction of two new offences to replace the unconstitutional section.
Murphy was appointed to the High Court in April 2014. She currently serves on the Superior Courts Rules Committee.
She has heard cases including those involving aspects of criminal law, judicial review, company law, employment law, and repossessions. She regularly presides over homicide and sexual offences cases.