Sir Edmund John Monson, 1st Baronet GCB GCMG GCVO PC (6 October 1834 – 28 October 1909), misspelled in some sources as Edward Monson, was a British diplomat who was minister or ambassador to several countries.

The Hon. Edmund John Monson was born at Seal, Kent, the third son of William Monson, 6th Baron Monson and Eliza Larken Monson. He was educated at Eton College and then Balliol College, Oxford, graduating in 1855, and was elected as a Fellow of All Souls College, Oxford in 1858.

Monson entered the British diplomatic service in 1856 and was posted as an unpaid attaché to the embassy in Paris, where Lord Cowley, the ambassador, called him "one of the best and most intelligent attachés he ever had". This secured him an appointment as private secretary to Lord Lyons, the newly appointed British minister in Washington late in 1858. He then transferred to Hanover and later to Brussels as Third Secretary, but left the diplomatic service in 1865 to stand for Parliament, failing to get elected as Member of Parliament for Reigate.

Monson returned to the diplomatic service in 1869, being appointed Consul in the Azores in 1869] Consul-General in Budapest in 1871 and Second Secretary in Vienna; and to other posts, including as a special envoy in Dalmatia and Montenegro in 1876-77.

In 1879, he was sent as minister-resident and consul-general in Uruguay, where he served until 1884. In 1881, during his time there, he married Eleanor Catherine Mary Munro, the daughter of a previous consul-general. In 1884 he became minister to Argentina and Paraguay, but returned to Europe within a year as envoy to Denmark (1884–88) and then to Greece (1888–92).

Shortly after Monson moved to Athens, the United States and Danish governments asked him to resolve a dispute known as the Butterfield Claims that had been running since 1854 and 1855, when two ships belonging to Carlos Butterfield & Co., thought to be carrying war materials to Venezuela, were detained at St Thomas, then a Danish colony. The two governments agreed, "whereas each of the parties hereto has entire confidence in the learning ability and impartiality of Sir Edmund Monson Her British Majesty's Envoy extraordinary and Minister plenipotentiary in Athens", to submit the dispute to his binding arbitration. Monson decided against the United States, but "so satisfied was this [U.S.] government with the judgement of Sir Edmund that it joined Denmark in presenting to him a service of silver plate".

Monson was appointed minister to Belgium in February 1892, but before he had left Athens a political crisis blew up in which King George I used his constitutional authority to dismiss the prime minister, Theodoros Deligiannis, resulting in an election in which Deligiannis lost power. The Times correspondent in Athens commented "It is to be hoped that Sir Edmund Monson, though already appointed to Brussels, may be allowed to remain here for some little time longer. On all sides regrets are expressed that an English diplomatic representative who is so thoroughly acquainted with Greek affairs, and who has gained the sympathy and confidence of all parties, should leave the country at this critical time." However, Monson arrived in Brussels on 25 June.

In 1893 Monson was promoted to ambassador, first to Austria and then in 1896 to France.