The position of secretary of state for dominion affairs was a secretary of state in the Government of the United Kingdom, responsible for British relations with the Empire’s dominions – Canada, Australia, New Zealand, South Africa, Newfoundland, and the Irish Free State – and the self-governing Crown colony of Southern Rhodesia.
When initially created in 1925, the office was held in tandem with that of secretary of state for the colonies; this arrangement persisted until June 1930. On two subsequent occasions the offices were briefly held by the same person.
The secretary of state was supported by an under-secretary of state for dominion affairs. In 1947, the name of the office was changed to the secretary of state for commonwealth relations.
Secretaries of state for dominion affairs, 1925–1947
{| class="wikitable" style="text-align:Center;"
! colspan=9 |
|-
! colspan=2| Portrait
! Name<br/><small>Honorifics & constituency</small>
! colspan=2|Term of office
! Political party
! colspan=2|Prime Minister
! Foreign Secretary
|-
| style="background-color: " |
| 60px
| Leo Amery<br><small>MP for Birmingham Sparkbrook</small><br><small>(also Sec.State for the Colonies)</small>
| <small>11 June</small><br>1925
| <small>4 June</small><br>1929
| Conservative
| style="background-color: " |
| Baldwin
| Chamberlain
|-
| style="background-color: " |
| 60px
| Sidney Webb, 1st Baron Passfield<br><small>(also Sec.State for the Colonies)</small>
| <small>7 June</small><br>1929
| <small>5 June</small><br>1930
| Labour
| rowspan=2 style="background-color: " |
| rowspan=3|MacDonald
| rowspan=2|Henderson
|-
| style="background-color: " |
| rowspan=2 | 60px
| rowspan=2 | James Henry Thomas<br><small>MP for Derby</small><br><small>(also Sec.State for the Colonies, Aug–Nov 1931)</small>
| rowspan=2 | <small>5 June</small><br>1930
| rowspan=2 | <small>22 November</small><br>1935
| Labour
|-
| style="background-color: " |
| National Labour
| style="background-color: " |
| Reading
----
Simon
|-
| rowspan=2 style="background-color: " |
| rowspan=2 | 60px
| rowspan=2 | Malcolm MacDonald<br><small>MP for Ross and Cromarty</small>
| rowspan=2 | <small>22 November</small><br>1935
| rowspan=2 | <small>16 May</small><br>1938
| rowspan=2 | National Labour
| style="background-color: " |
| Baldwin
| rowspan="2"|Hoare
----
Eden
|-
| height=15 style="background-color: " |
| rowspan="5"|Chamberlain
|-
| style="background-color: " |
| 60px
| Edward Stanley, Lord Stanley<br><small>MP for Fylde</small>
| <small>16 May</small><br>1938
| <small>16 October</small><br>1938†
| Conservative
| rowspan=4 style="background-color: " |
| rowspan=5 | Halifax
|-
| style="background-color: " |
| 60px
| Malcolm MacDonald<br><small>MP for Ross and Cromarty</small><br><small>(also Sec.State for the Colonies)</small>
| <small>31 October</small><br>1938
| <small>29 January</small><br>1939
| National Labour
|-
| style="background-color: " |
| 60px
| Sir Thomas Inskip<br><small>MP for Fareham</small>
| <small>29 January</small><br>1939
| <small>3 September</small><br>1939
| Conservative
|-
| style="background-color: " |
| 60px
| Anthony Eden<br><small>MP for Warwick and Leamington</small>
| <small>3 September</small><br>1939
| <small>14 May</small><br>1940
| Conservative
|-
| style="background-color: " |
| 60px
| Thomas Inskip, 1st Viscount Caldecote
| <small>14 May</small><br>1940
| <small>3 October</small><br>1940
| Conservative
| rowspan=4 style="background-color: " |
| rowspan=4|Churchill
|-
| style="background-color: " |
| 60px
| Robert Gascoyne-Cecil, Viscount Cranborne<br><small>MP for South Dorset</small> <small>until 1941</small><br>Baron Cecil of Essendon <small>after 1941</small>
| <small>3 October</small><br>1940
| <small>19 February</small><br>1942
| Conservative
| rowspan=3|Eden
|-
| style="background-color: " |
| 60px
| Clement Attlee<br><small>MP for Limehouse</small>
| <small>19 February</small><br>1942
| <small>24 September</small><br>1943
| Labour
|-
| style="background-color: " |
| 60px
| Robert Gascoyne-Cecil, Viscount Cranborne<br><small>Baron Cecil of Essendon</small>