The Fourth Lyons ministry (United Australia–Country Coalition) was the 23rd ministry of the Government of Australia. It was led by the country's 10th Prime Minister, Joseph Lyons. The Fourth Lyons ministry succeeded the Third Lyons ministry, which dissolved on 29 November 1937 following the federal election that took place in October. The ministry was replaced by the Page ministry on 7 April 1939, following the death of Lyons — the first of three occasions on which a prime minister had died in office.
John McEwen, who died in 1980, was the last surviving member of the Fourth Lyons ministry; McEwen was also the last surviving member of the Page ministry. Robert Menzies was the last surviving UAP minister.
Ministry
{| class="wikitable sortable"
!colspan="2"|Party
! Minister
! Portrait
! Portfolio
|-
| | ||United Australia
| Joseph Lyons <br>
for Wilmot <br>
| 100px
|
- Prime Minister
- Leader of the United Australia Party
|-
| | ||Country
| Sir Earle Page <br>
for Cowper <br>
| 100px
|
- Leader of the Country Party
- Minister for Commerce
- Minister for Health <small>(to 7 November 1938)</small>
|-
| | ||United Australia
| Robert Menzies <br>
for Kooyong <br>
| 100px
|
- Deputy Leader of the United Australia Party <small>(to 20 March 1939)</small>
- Attorney-General <small>(to 20 March 1939)</small>
- Minister for Industry <small>(to 20 March 1939)</small>
|-
| | ||United Australia
| Alexander McLachlan <br>
Senator for South Australia <br>
| 100px
|
- Postmaster-General <small>(to 7 November 1938)</small>
- Leader of the Government in the Senate <small>(to 7 November 1938)</small>
|-
| | ||United Australia
| Thomas White <br>
for Balaclava <br>
| 100px
|
- Minister for Trade and Customs <small>(to 8 November 1938)</small>
|-
| | ||United Australia
| Richard Casey <br>
for Corio <br>
| 100px
|
- Treasurer
- Minister in charge of Development and Scientific and Industrial Research <small>(to 7 November 1938)</small>
|-
| | ||United Australia
| Billy Hughes <br>
for North Sydney <br>
| 100px
|
- Minister for External Affairs
- Vice-President of the Executive Council <small>(to 7 November 1938)</small>
- Minister in charge of Territories <small>(to 7 November 1938)</small>
- Attorney-General <small>(from 20 March 1939)</small>
- Minister for Industry <small>(from 20 March 1939)</small>
|-
| | ||Country
| Harold Thorby <br>
for Calare <br>
| 100px
|
- Deputy Leader of the Country Party
- Minister for Defence <small>(to 7 November 1938)</small>
- Minister for Works <small>(from 7 November 1938)</small>
- Minister for Civil Aviation <small>(from 7 November 1938)</small>
|-
| | ||United Australia
| Harry Foll <br>
Senator for Queensland <br>
| 100px
|
- Minister in charge of War Service Homes <small>(to 7 November 1938)</small>
- Minister for Repatriation <small>(from 7 November 1938)</small>
- Minister for Health <small>(from 7 November 1938)</small>
|-
| | ||Country
| John McEwen <br>
for Indi <br>
| 100px
|
- Minister for the Interior
|-
| | ||Country
| Archie Cameron <br>
for Barker <br>
| 100px
|
- Minister without portfolio assisting the Minister for Commerce <small>(to 7 November 1938)</small>
- Postmaster-General <small>(from 7 November 1938)</small>
|-
| | ||Country
| Victor Thompson <br>
for New England <br>
| 100px
|
- Minister without portfolio assisting the Minister for Commerce
|-
| | ||United Australia
| Allan MacDonald <br>
Senator for Western Australia <br>
| 100px
|
- Minister without portfolio assisting the Minister for Commerce <small>(to 7 November 1938)</small>
- Minister without portfolio assisting the Treasurer <small>(from 7 November 1938)</small>
|-
| | ||United Australia
| George McLeay <br>
Senator for South Australia <br>
<small>(in Ministry from 7 November 1938)</small>
| 100px
|
- Chief Government Whip in the Senate <small>(to 29 November 1937)</small>
- Vice-President of the Executive Council <small>(from 7 November 1938)</small>
- Leader of the Government in the Senate <small>(from 7 November 1938)</small>
|-
| | ||United Australia
| Geoffrey Street <br>
for Corangamite <br>
<small>(in Ministry from 7 November 1938)</small>
| 100px
|
- Minister for Defence <small>(from 7 November 1938)</small>
|-
| | ||United Australia
| John Perkins <br>
for Eden-Monaro <br>
<small>(in Ministry from 7 November 1938)</small>
| 100px
|
- Minister without portfolio administering external territories <small>(from 7 November 1938 to 8 November 1938)</small>
- Minister without portfolio assisting the Prime Minister <small>(from 7 November 1938 to 8 November 1938)</small>
- Minister for Trade and Customs <small>(from 8 November 1938)</small>
|-
| | ||United Australia
| Eric Harrison <br>
for Wentworth <br>
<small>(in Ministry from 8 November 1938)</small>
| 100px
|
- Minister without portfolio administering external territories <small>(from 8 November 1938)</small>
- Minister without portfolio assisting the Prime Minister <small>(from 8 November 1938)</small>
|}