| Horace Holmes Thomas | |
| Office1: | Member of the Illinois Senate from the 6th District |
| Term Start1: | January 9, 1889 |
| Term End1: | July 22, 1890 |
| Predecessor1: | Henry W. Leman |
| Successor1: | Jacob Miller |
| Office2: | 29th Speaker of the Illinois House of Representatives |
| Term Start2: | January 5, 1881 |
| Term End2: | January 3, 1883 |
| Predecessor2: | William A. James |
| Successor2: | Lorin C. Collins |
| Office3: | Member of the Illinois House of Representatives from the 6th District of Cook County |
| Term Start3: | January 8, 1879 |
| Term End3: | January 3, 1883 |
| Alongside3: | Christian Meyer, Austin Sexton, Lorin C. Collins, George G. Struckman, Bernhast F. Weber |
| Predecessor3: | Various (multimember district) |
| Successor3: | Various (multimember district) |
| Birth Date: | 18 December 1831 |
| Birth Place: | Hubbardton, Vermont, U.S. |
| Death Place: | Chicago, Illinois, U.S. |
| Party: | Republican |
| Spouse: | Annie Greenough Hale (m. 1870) |
| Children: | 1 |
| Education: | Middlebury College |
| Profession: | Attorney |
| Allegiance: | United States Union |
| Branch: | Union Army Tennessee Militia |
| Rank: | Captain (Union Army) Brigadier General (Militia) |
| Serviceyears: | 1861–1865 (Union Army) 1865–1867 (Militia) |
| Commands: | Quartermaster General, Tennessee Militia |
| Unit: | 8th Tennessee Infantry (Union Army) 3rd Division, II Corps (Union Army) Staff of Governor William G. Brownlow (Militia) |
| Battles: | American Civil War |
Horace Holmes Thomas (December 18, 1831 – March 17, 1904) was a lawyer, Union Army officer, state legislator, and appraiser in Illinois who served in the Illinois House of Representatives and Illinois Senate.[1] He was a Speaker of the Illinois House of Representatives from 1880 to 1881.[2]
He was born in Hubbardton, Vermont, graduated from Middlebury College, and studied law.[2] He moved to Chicago in 1859.[2]
He was an officer in the Union Army during the American Civil War.[3] He wrote about his Civil War experiences.[2] He married and had a daughter.[4] He was written about by the Grand Army Hall and Memorial Association of Illinois in 1904.[5]