| Honorific-Prefix: | The Honourable |
| William Henry Brouse | |
| Constituency Mp: | Grenville South |
| Parliament: | Canadian |
| Predecessor: | Walter Shanly |
| Successor: | John Philip Wiser |
| Term Start: | 1872 |
| Term End: | 1878 |
| Office2: | Senator for Prescott, Ontario |
| Appointed2: | Alexander Mackenzie |
| Term Start2: | August 9, 1878 |
| Term End2: | August 23, 1881 |
| Birth Date: | 15 June 1824 |
| Birth Place: | Matilda Township, Dundas County, Upper Canada |
| Death Place: | Ottawa, Ontario, Canada |
| Party: | Liberal |
| Allegiance: | Canada |
| Branch: | Canadian Militia |
| Unit: | 56th (Grenville) Battalion of Infantry |
| Serviceyears: | 1867-1880s |
| Rank: | Surgeon |
| Battles: | Fenian Raids |
William Henry Brouse (June 15, 1824 - August 23, 1881) was a Canadian physician and politician.
Born in Matilda Township, Dundas County, Upper Canada of German ancestry, his father was Colonel Jacob Brouse of the Dundas Militia who was one of the first to fire upon the American Army at the Battle of Point Iroquois and commanded the 4th (Winchester) Battalion in the 1850s.
William Brouse attended Upper Canada Academy in Cobourg, Canada West in 1839, Victoria College until 1845, and received his Doctor of Medicine degree in 1847 from McGill College.
He was first elected to the House of Commons of Canada representing the Ontario riding of Grenville South in the 1872 federal election. A Liberal, he was re-elected in 1874. He was nominated to the Senate of Canada in 1878 representing the senatorial division of Prescott, Ontario, and sat as a Reformer until his death in 1881.
He was commissioned as the Surgeon of the 56th (Grenville) Battalion of Infantry on April 12, 1867, and was active in matters of the Canadian Militia. He successfully campaigned for, a $50,000 annual grant for the veterans of the War of 1812 and he proposed, unsuccessfully, that recognition be granted to the militia veterans of the rebellions of 1837–38.
He was the nephew of George Brouse, an Upper Canada MP.