The 4th Parliament of Upper Canada was opened 1 February 1805. Elections in Upper Canada had been held in May 1804. All sessions were held at Parliament Buildings of Upper Canada in York, Upper Canada. This parliament was dissolved 21 May 1808.
|1st||1 February 1805||2 March 1805|
|2nd||4 February 1806||3 March 1806|
|3rd||2 February 1807||10 March 1807|
|4th||20 January 1808||16 March 1808|
|Durham, Simcoe & 1st York||Angus Macdonell|
|Robert Thorpe (January 1807)|
|Glengarry & Prescott||Alexander Macdonell - Speaker 1804-1808|
|Glengarry & Prescott||Walter Butler Wilkinson|
|Hastings & Northumberland||David McGregor Rogers|
|Lennox & Addington||Thomas Dorland|
|2nd, 3rd, 4th Lincoln||Ralfe Clench|
|2nd, 3rd, 4th Lincoln||Isaac Swayze|
|2nd Lincoln||Samuel Street|
|Norfolk, Oxford & Middlesex||Benajah Mallory|
|Prince Edward||Ebenezer Washburn|
|Stormont & Russell||Robert Isaac Dey Gray|
|D'Arcy Boulton (February 1806)|
|West York, 1st Lincoln & Haldimand||Robert Nelles|
|West York, 1st Lincoln & Haldimand||Solomon Hill|
|Joseph Willcocks (January 1808)|
- Archives of Ontario "The Statutes of Upper Canada and the Province of Canada". Archived from the original on 11 June 2011. Retrieved 2009-12-07.
- died in 1804; replaced by William Weekes in February 1805
- died in October 1806. Robert Thorpe took his place in January 1807.
- died in 1804
- died in August 1807 and Joseph Willcocks took his place in January 1808.