During the Ninth Parliament of Sri Lanka, which commenced on August 20, 2020, and was dissolved by the President at midnight on September 24, 2024, there were 19 vacancies in Parliamentary seats as per Article 66 of the Constitution.

Consequently, 16 new Members of Parliament were appointed on 18 occasions.

In total, 241 MPs served in the Ninth Parliament. 

Notable changes included the resignation of Jayantha Katagoda, who was replaced by Basil Rajapaksa. 

Later, Ajith Nivard Cabral resigned, and Jayantha Katagoda was reappointed. 

Similarly, A.H.M. Fowzie filled the vacancy left by Mujibar Rahman, who was later reappointed to the seat vacated by Diana Gamage due to a court decision. 

However, no new MP was appointed for the seat vacated by Harin Fernando.

A significant event during this term was the election of Ranil Wickramasinghe as the 8th Executive President of Sri Lanka, following the resignation of the 7th Executive President, Gotabaya Rajapaksa. 

This led to the appointment of a new MP to replace Ranil Wickramasinghe’s Parliamentary seat.

The Ninth Parliament experienced four prorogations: the first two by former President Gotabaya Rajapaksa, and the third and fourth by former President Ranil Wickremesinghe.

Five sessions were held during this period: the first from August 20, 2020, to December 12, 2021; the second from January 18, 2022, to July 28, 2022; the third from August 3, 2022, to January 27, 2023; the fourth from February 8, 2023, to January 26, 2024; and the fifth from February 7, 2024, until the dissolution of Parliament on September 24, 2024.

Throughout these five sessions, Parliament convened for a total of 390 days.