Sir Helenus Milmo, QC (born Helenus Padraic Seosamh Milmo; 24 August 1908 – 1988) was a British lawyer and High Court judge. His career was notable for his role in the prosecution team at the Nuremberg Trials.
He was born in County Limerick on 24 August 1908, the third son of Daniel and Kathleen (née White) Milmo, but spent his early years in Furbogh, Galway Gaeltacht. He was a distant nephew of Don Patricio Milmo O'Dowd (né Patrick Milmo; 1826-1899), who emigrated to Mexico and became a successful businessman and banker.
Milmo failed to elicit definitive answers  and concluded "that Philby is and has been for many years a Soviet agent. But the case remained unproven." Milmo's peers were not entirely forgiving. "Some felt", wrote Peter Carter-Ruck when Milmo died in 1988, "that he was perhaps too much of a gentleman for that daunting task."
Milmo married Joan Frances Morley (9 March 1907-June 1978), the second daughter of Francis Morley of Sloan Court, London, in 1933. The couple had five children:
- Deirdre (born 1934)
- Patrick, QC (born 1938), a barrister
- Verity (born 1941)
- Shaun (born 1943), a journalist
- Patricia (born 1949/1950), a solicitor; she married Bennett Umunna in 1976
Joan Milmo predeceased her husband in 1978, aged 71, from undisclosed causes. He married, secondly, in 1980, to Mrs. Anne Brand, the widow of Francis Bernard Brand. Mrs. Brand was born Anne Gilmore O'Connell, the daughter of Maurice William O'Connell. Sir Helenus Milmo died in 1988 in Chichester, West Sussex. Anne, Lady Milmo (born 27 May 1907 – died 28 November 2003) died at age 96.
- Name anglicized on death registration, familysearch.org; accessed 30 November 2014.
- "Ireland, Civil Registration Indexes, 1845-1958" index, FamilySearch (https://familysearch.org/pal:/MM9.1.1/FBPQ-R6B; accessed 12 March 2014), BIRTHS entry for Helenus Padraic Seosamh Milmo; citing Limerick, July-September 1908, vol. 5, p. 334, General Registry, Custom House, Dublin; FHL microfilm 101072.
- "Nobody is talking" The Guardian, 18 February 2005
- "How MI5 spent 18 years hunting the spy it had already caught", The Times, 6 October 2009.
- "The British Obama? No, Labour high-flyer Chuka's the black Blair". Daily Mail. 30 September 2012.
- Notice of death of Anne, Lady Milmo, groups.google.com; accessed 30 November 2014.
- Image at National Portrait Gallery (NPG), npg.org.uk; accessed 30 November 2014.