1970s
| Year | Date | Event |
| 1970 | 2 March | Rhodesia declares itself a republic and a new constitution takes effect. |
| 4 June | Tonga joins the Commonwealth upon being granted independence by the United Kingdom. | |
| 1 July | Arnold Smith begins his second term as Commonwealth Secretary-General. | |
| 16 July | The 1970 British Commonwealth Games open in Edinburgh, the United Kingdom. It was the first time the Games use the metric system. | |
| 28 August | Samoa joins the Commonwealth, having gained independence from New Zealand in 1962. | |
| 10 October | Fiji joins the Commonwealth upon being granted independence by the United Kingdom. | |
| 1971 | 14 January | The first Commonwealth Heads of Government Meeting convenes in Singapore. |
| 22 January | At the conclusion of the first CHOGM, the assembled Commonwealth Heads of Government issue the Singapore Declaration, setting out the core political values of the Commonwealth. It is considered, along with the 1991 Harare Declaration, one of the two most important documents of the Commonwealth's constitution. | |
| 26 March | East Pakistan declares its independence as Bangladesh. | |
| 3 December | India intervenes in Bangladesh, sparking the Indo-Pakistani War of 1971. | |
| 16 December | Pakistan surrenders to India, ending the war. | |
| 1972 | 18 April | Bangladesh joins the Commonwealth, having gained independence from Pakistan the previous year. |
| 1973 | 10 July | The Bahamas joins the Commonwealth upon being granted independence by the United Kingdom. |
| 2 August | The second Commonwealth Heads of Government Meeting convenes in Ottawa, Canada. | |
| 1974 | 24 January | The 1974 British Commonwealth Games open in Christchurch, New Zealand. It is the last time that the Games' name includes reference to the United Kingdom. |
| 7 February | Grenada joins the Commonwealth upon being granted independence by the United Kingdom. | |
| 1975 | 29 April | The third Commonwealth Heads of Government Meeting convenes in Kingston, Jamaica. |
| 1 July | Guyana's Shridath Ramphal succeeds Arnold Smith as Commonwealth Secretary-General. | |
| 16 September | Papua New Guinea joins the Commonwealth upon being granted independence by Australia. | |
| 1976 | 29 June | Seychelles joins the Commonwealth upon being granted independence by the United Kingdom. |
| 1977 | 8 June | The fourth Commonwealth Heads of Government Meeting convenes in London, the United Kingdom. |
| 1978 | 7 July | The Solomon Islands joins the Commonwealth upon being granted independence by the United Kingdom. |
| 3 August | The 1978 Commonwealth Games open in Edmonton, Canada. It is the first time that the Games are held under the current name. | |
| 1 October | Tuvalu joins the Commonwealth upon being granted independence by the United Kingdom. | |
| 3 November | Dominica joins the Commonwealth upon being granted independence by the United Kingdom. | |
| 1979 | 12 July | Kiribati joins the Commonwealth upon being granted independence by the United Kingdom. |
| 1 August | The fifth Commonwealth Heads of Government Meeting convenes in Lusaka, Zambia. | |
| 7 August | At the conclusion of the fifth CHOGM, the assembled Commonwealth Heads of Government issue the Lusaka Declaration, reaffirming the Commonwealth's opposition to racism and demanding legal equality for all people of the Commonwealth. | |
| 27 October | Saint Vincent and the Grenadines joins the Commonwealth upon being granted independence by the United Kingdom. | |
| 12 December | Zimbabwe Rhodesia dissolves itself, returning power to the United Kingdom (formally as Southern Rhodesia) in preparation for recognised independence. | |
| 21 December | The Lancaster House Agreement is reached, setting the terms of independence for Southern Rhodesia. |
Read more about this topic: Timeline Of Commonwealth Of Nations History