Template:43rd Ontario Legislature membership changes
| Seat | Date | Member | Reason | Previous Party | Party After |
|---|---|---|---|---|---|
| Hamilton Centre | August 15, 2022 | Andrea Horwath | Resigned from the legislature to run in the 2022 Hamilton municipal election. | █ New Democratic | Vacant |
| Don Valley North | March 10, 2023 | Vincent Ke | Resigned from caucus after allegations surfaced of involvement with Chinese government election interference. | █ PC | █ Independent |
| Hamilton Centre | March 16, 2023 | Sarah Jama | Won by-election to replace Andrea Horwath. | Vacant | █ New Democratic |
| Kanata—Carleton | March 27, 2023 | Merrilee Fullerton | Resigned from the legislature for undisclosed reasons. | █ PC | Vacant |
| Algoma—Manitoulin | March 31, 2023 | Michael Mantha | Removed from caucus due to allegations involving workplace misconduct. | █ New Democratic | █ Independent |
| Scarborough—Guildwood | May 10, 2023 | Mitzie Hunter | Resigned from the legislature to run in the 2023 Toronto mayoral by-election. | █ Liberal | Vacant |
| Kitchener Centre | July 13, 2023 | Laura Mae Lindo | Resigned from the legislature to take a teaching position at the University of Waterloo. | █ New Democratic | Vacant |
| Kanata—Carleton | July 27, 2023 | Karen McCrimmon | Won by-election to replace Merrilee Fullerton. | Vacant | █ Liberal |
| Scarborough—Guildwood | July 27, 2023 | Andrea Hazell | Won by-election to replace Mitzie Hunter. | Vacant | █ Liberal |
| Mississauga East—Cooksville | September 20, 2023 | Kaleed Rasheed | Resigned from caucus after contradictory claims were made regarding a Las Vegas business trip. | █ PC | █ Independent |
| Lambton—Kent—Middlesex | October 6, 2023 | Monte McNaughton | Resigned from the legislature to pursue a career opportunity in the private sector. | █ PC | Vacant |
| Hamilton Centre | October 23, 2023 | Sarah Jama | Removed from caucus over controversial statements made regarding the Israel–Hamas war. | █ New Democratic | █ Independent |
| Kitchener Centre | November 30, 2023 | Aislinn Clancy | Won by-election to replace Laura Mae Lindo. | Vacant | █ Green |
| Milton | January 25, 2024 | Parm Gill | Resigned from the legislature to run in a future federal election for the Conservative Party of Canada. | █ PC | Vacant |
| Lambton—Kent—Middlesex | May 2, 2024 | Steve Pinsonneault | Won by-election to replace Monte McNaughton. | Vacant | █ PC |
| Milton | May 2, 2024 | Zee Hamid | Won by-election to replace Parm Gill. | Vacant | █ PC |