12th Parliament of Upper Canada
The 12th Parliament of Upper Canada was opened 15 January 1835. Elections in Upper Canada had been held in October 1834. All sessions were held at York, Upper Canada. This parliament was dissolved 28 May 1836 by the new Lieutenant Governor, Sir Francis Bond Head. Head ordered a new election because the House of Assembly, dominated by reformers, had refused to pass any new money bills. The assembly also labelled Head a deceitful tyrant after he had invoked his right to consult them only on certain specific matters. It was succeeded by the 13th Parliament of Upper Canada in November 1836.
The House of Assembly of the 12th Parliament of Upper Canada had two sessions 4 February 1817 to 7 March 1820:
Both the House and Parliament sat at the third Parliament Buildings of Upper Canada.
| Sessions | Start | End |
| 1st | 15 January 1835 | 16 April 1835 |
| 2nd | 14 January 1836 | 20 April 1836 |
| Riding | Member |
| Brockville | David Jones |
| Carleton | Edward Malloch |
| Carleton | John Bower Lewis |
| Cornwall | Archibald McLean - Speaker 1836 |
| Dundas | Peter Shaver |
| Dundas | John Cook |
| Durham | George Strange Boulton |
| Durham | John Brown |
| Essex | Francis Xavier Caldwell |
| Essex | John Alexander Wilkinson |
| Frontenac | Jacob Shibley |
| Frontenac | John Strange |
| Glengarry | Donald Macdonell |
| Glengarry | Alexander Chisholm |
| Grenville | Hiram Norton |
| Grenville | William Benjamin Wells |
| Haldimand | William Hamilton Merritt |
| Halton | Caleb Hopkins |
| Halton | James Durand, Jr. |
| Hamilton | Allan Napier MacNab |
| Hastings | Henry W. Yager |
| Hastings | James Hunter Samson |
| Huron | Robert Graham Dunlop |
| Kent | William McCrae |
| Kent | Nathan Cornwall |
| Kingston | Christopher Alexander Hagerman |
| Lanark | William Morris |
| Alexander Thom | |
| Lanark | Josias Tayler |
| Leeds | Ogle Robert Gowan |
| William Buell | |
| Leeds | Robert Sympson Jameson |
| Matthew M. Howard | |
| Lennox & Addington | Marshall Spring Bidwell - Speaker 1835 |
| Lennox & Addington | Peter Perry |
| 1st Lincoln County | Dennis Woolverton |
| 2nd Lincoln | George Rykert |
| 3rd Lincoln | John Johnston Lefferty |
| David Thorburn | |
| 4th Lincoln | Gilbert McMicking |
| Middlesex | Thomas Parke |
| Middlesex | Elias Moore |
| Niagara | Charles Richardson |
| Norfolk | Francis Leigh Walsh |
| Norfolk | David Duncombe |
| Northumberland | Alexander McDonell |
| Northumberland | John Gilchrist |
| Oxford | Charles Duncombe |
| Oxford | Robert Alway |
| Prescott | Alexander MacDonell of Greenfield |
| John Chesser | |
| Prescott | Charles Waters |
| Prince Edward | John Philip Roblin |
| Prince Edward | James Wilson |
| Russell | Thomas McKay |
| Simcoe | William Benjamin Robinson |
| Simcoe | Samuel Lount |
| Stormont | William Bruce |
| Stormont | Donald Aeneas MacDonell |
| Toronto | James Edward Small |
| Wentworth | Harmannus Smith |
| Wentworth | Jacob Rymal |
| 1st York | David Gibson |
| 2nd York | William Lyon Mackenzie |
| 3rd York | Thomas David Morrison |
| 4th York | John McIntosh |