| Sir Odo Russell | |
| Honorific Suffix: | KCMG KCVO CB |
| Office: | British Minister to the Netherlands |
| Term Start: | 1928 |
| Term End: | 1933 |
| Predecessor: | The Earl Granville |
| Successor: | Sir Hubert Montgomery |
| Office1: | British Minister on a Special Mission to His Holiness the Pope |
| Term Start1: | 1922 |
| Term End1: | 1928 |
| Predecessor1: | The Count de Salis-Soglio |
| Successor1: | Sir Henry Chilton |
| Office2: | Brititsh Minister to the Swiss Confederation |
| Term Start2: | 1919 |
| Term End2: | 1922 |
| Successor2: | Sir Milne Cheetham |
| Birth Name: | Odo William Theophilus Russell |
| Parents: | Odo Russell, 1st Baron Ampthill Lady Emily Villiers |
| Children: | 3 |
| Relations: | Arthur Russell, 2nd Baron Ampthill (brother) Lord George Russell (grandfather) |
Sir Odo William Theophilus Russell (3 May 1870 – 23 December 1951) was a British diplomat who was ambassador to Switzerland, the Vatican and the Netherlands.
Russell was the second son of Odo Russell, later the first Baron Ampthill, by Lady Emily Villiers, daughter of George Villiers, 4th Earl of Clarendon and Lady Katherine Grimston (daughter of the 1st Earl of Verulam). His elder brother was Arthur Russell, 2nd Baron Ampthill.
His paternal grandparents were Maj.-Gen. Lord George Russell (second son of the 6th Duke of Bedford) and Elizabeth Anne Rawdon (niece of the 1st Marquess of Hastings). His grand-uncle was the 1st Earl Russell, twice Prime Minister of the United Kingdom.
Russell entered the Diplomatic Service in 1892 and served in Rome, Athens, St Petersburg, Berlin, Buenos Aires and Vienna, where he held the rank of counsellor from 1909 to 1915. He was then Diplomatic Secretary to the Secretary of State for Foreign Affairs from 1915 to 1919, Minister at Bern from 1919 to 1922, Minister to the Holy See from 1922 to 1928 and Minister at The Hague from 1928 to 1933 (the last three posts were equivalent to modern ambassadorships). He was appointed Commander of the Royal Victorian Order (CVO) in 1909, Companion of the Order of the Bath (CB) in 1916, Knight Commander of the Royal Victorian Order (KCVO) in 1923 and Knight Commander of the Order of St Michael and St George (KCMG) in 1926.
On 25 June 1910, while he was stationed in Vienna, Russell married Countess Marie Louise von Rex (10 July 1890 – 16 November 1966), daughter of Count Rudolf Karl Caspar von Rex, the Saxon Minister at the Austro-Hungarian Court. Together, they had three sons:
Russell and his wife, the Countess, are buried in the churchyard of St Michael's, Chenies, together with other members of the Russell family.[2]