The Under-Secretary of State for War and the Colonies was a junior Ministerial post in the United Kingdom government, subordinate to the Secretary of State for War and the Colonies.
In 1801 the offices of Under-Secretary of State for War and Under-Secretary of State for the Colonies were merged to create the new office. They were separated again in 1854.
Under-Secretaries of State for War and the Colonies, 1801-1854
{| class="wikitable" style="text-align:left"
|-
! Name !! Entered office !! Left office
|-
|John Sullivan || 1801 || 1804
|-
|Edward Cooke || 1804 || 1806
|-
|Sir George Shee, 1st Baronet <br /> and Sir James Cockburn, 9th Baronet || 1806 || 1807
|-
|Edward Cooke <br /> and Charles Stewart || 1807 || 1809
|-
|Frederick Robinson <br /> and Charles Jenkinson || 1809 || 1809
|-
|Charles Jenkinson <br /> and Henry Bunbury || 1809 || 1810
|-
|Henry Bunbury <br /> and Robert Peel|| 1810 || 1812
|-
|Henry Bunbury <br /> and Henry Goulburn || 1812 || 1816
|-
|Henry Goulburn|| 1816 || 1821
|-
|R. W. Horton|| 1821 || 1827
|-
|Edward Stanley|| 1827 || 1828
|-
|Lord Francis Leveson-Gower || 1828 || 1828
|-
|Horace Twiss || 1828 || 1830
|-
|Henry Grey, Viscount Howick || 1830 || 1833
|-
|Sir John George Shaw-Lefevre|| 1833 || 1834
|-
|Sir George Grey, 2nd Baronet || 1834 || 1834
|-
|John Stuart-Wortley || 1834 || 1835
|-
|William Ewart Gladstone|| 1835 || 1835
|-
|Sir George Grey, 2nd Baronet || 1835 || 1839
|-
|Henry Labouchere || 1839 || 1839
|-
|Robert Vernon Smith || 1839 || 1841
|-
|George William Hope || 1841 || 1846
|-
|George Lyttelton, 4th Baron Lyttelton || 1846 || 1846
|-
|Benjamin Hawes || 1846 || 1851
|-
|Frederick Peel || 1851 || 1852
|-
|John Cuffe, 3rd Earl of Desart || 1852 || 1852
|-
|Frederick Peel || 1852 || 1854
|}
Separate posts of Under-Secretary of State for War and Under-Secretary of State for the Colonies re-established 1854