| Honorific-Prefix: | The Right Honourable |
| Viscount Macmillan of Ovenden | |
| Office: | Paymaster General |
| Primeminister: | Edward Heath |
| Term Start: | 2 December 1973 |
| Term End: | 4 March 1974 |
| Predecessor: | The Viscount Eccles |
| Successor: | Edmund Dell |
| Office1: | Secretary of State for Employment |
| Primeminister1: | Edward Heath |
| Term Start1: | 7 April 1972 |
| Term End1: | 2 December 1973 |
| Predecessor1: | Robert Carr |
| Successor1: | William Whitelaw |
| Office2: | Chief Secretary to the Treasury |
| Primeminister2: | Edward Heath |
| Term Start2: | 23 June 1970 |
| Term End2: | 7 April 1972 |
| Predecessor2: | Jack Diamond |
| Successor2: | Patrick Jenkin |
| Office3: | Member of Parliament for South West Surrey |
| Term Start3: | 9 June 1983 |
| Term End3: | 10 March 1984 |
| Predecessor3: | new constituency |
| Successor3: | Virginia Bottomley |
| Office4: | Member of Parliament for Farnham |
| Term Start4: | 31 March 1966 |
| Term End4: | 13 May 1983 |
| Predecessor4: | Godfrey Nicholson |
| Successor4: | constituency abolished |
| Office5: | Member of Parliament for Halifax |
| Term Start5: | 26 May 1955 |
| Term End5: | 25 September 1964 |
| Predecessor5: | Dryden Brook |
| Birth Date: | 27 January 1921 |
| Birth Place: | Westminster, London, England |
| Death Place: | Westminster, London, England |
| Education: | Eton College |
| Alma Mater: | Balliol College, Oxford |
Maurice Victor Macmillan, Viscount Macmillan of Ovenden, (27 January 1921 – 10 March 1984), was a British Conservative Party politician and Member of Parliament. He was the only son of Harold Macmillan, 1st Earl of Stockton, who was Prime Minister of the United Kingdom from 1957 to 1963.
Macmillan was the only son of Harold Macmillan, 1st Earl of Stockton, and Lady Dorothy Cavendish, daughter of Victor Cavendish, 9th Duke of Devonshire. He was educated at Eton and Balliol College, Oxford. He served with the Sussex Yeomanry in Europe in the Second World War. Like his father, he was chairman of Macmillan Publishers, as well as a director of two news agencies.
Macmillan contested Seaham at the 1945 election, Lincoln in 1951 and Wakefield at a 1954 by-election. He served on Kensington Borough Council from 1949 to 1953, then was elected MP for Halifax at the 1955 general election but lost this seat in 1964. He was then elected for Farnham in 1966. This latter seat became South West Surrey at the 1983 election. He served as Economic Secretary to the Treasury (1963–64) under Alec Douglas-Home, and as Chief Secretary to the Treasury (1970–72), Secretary of State for Employment (1972–73) and Paymaster General (1973–74) under Edward Heath. He was made a Privy Counsellor in 1972.
Macmillan married the Honourable Katharine Ormsby-Gore, daughter of William Ormsby-Gore, 4th Baron Harlech, on 22 August 1942. They had four sons and a daughter:
Macmillan was for a time the owner of Highgrove House, which he sold to the Prince of Wales in 1980. Upon his father's elevation to the peerage as Earl of Stockton on 24 February 1984, Macmillan acquired the courtesy title Viscount Macmillan of Ovenden. He held the title for just days, dying in Westminster, London, on 10 March 1984, following a heart operation. He was 63. His father outlived him by almost three years, dying in December 1986 at the age of 92.[3]
Macmillan's son Alexander has held the title 2nd Earl of Stockton since the death of the first Earl.