July 25, 2011: Jack Layton temporarily steps down as leader of the NDP, due to cancer, indicating his intention to return to the job for the reconvening of Parliament in September. Hull—Aylmer MP Nycole Turmel is chosen to act as NDP leader during the leave.[4]
August 22, 2011: Jack Layton dies of cancer. Turmel assumes the position of Leader of the Opposition.[5]
December 16, 2011: Royal assent is given to the Fair Representation Act, raising the number of seats to 338. Fifteen will be added to Ontario, six each to British Columbia and Alberta, and three to Quebec.
May 18, 2012: An Ontario Superior Court judge declares the 2011 federal election results in the riding of Etobicoke Centre to be "null and void", potentially triggering a by-election.[13][14]
May 28, 2012: Conservative MP Ted Opitz announces he will appeal to the Supreme Court of Canada to uphold the result in Etobicoke Centre.[15]
June 5, 2013: Edmonton—St. Albert MP Brent Rathgeber voluntarily leaves the Conservative caucus because of what he describes as "the Government's lack of commitment to transparency and open government",[30] one day after tabling a bill on government transparency.[31]
July 8, 2013: Minister of Public Safety Vic Toews resigns as Minister and as MP for Provencher, citing a desire to spend more time with his family.[33]
July 31, 2013: Former interim Liberal leader and Toronto Centre MP Bob Rae resigns in order to become First Nations negotiator in Northern Ontario.[34][35]
January 29, 2014: Justin Trudeau states that senate partisanship has interfered with senators' responsibilities, that the 32 Liberal senators were no longer part of the Liberal parliamentary caucus, and he had asked them to sit as independents.[44]
May 1, 2014: New electoral boundaries, which will increase the number of seats to 338, will come into effect upon the first dissolution of Parliament after this date.[23]
Dean Del Mastro, the independent MP for Peterborough, resigns his seat after being found guilty on three counts of violating election spending limits.[59][60] Prior to Del Mastro's resignation, the House of Commons was expected to vote in favour of an NDP proposal to suspend Del Mastro without pay, effective immediately.[59]
November 19, 2014: Independent MP Maria Mourani becomes a member of the NDP, but will continue to sit as an independent for the duration of the current Parliament per the NDP's policy against floor-crossing.[62]
March 18, 2015: Massimo Pacetti, independent (former Liberal) MP for Saint-Léonard—Saint-Michel, announces he will serve out his term as an independent and not run for reelection amid reports he is about to be permanently expelled from caucus.[66]
March 19, 2015: Scott Andrews, independent (former Liberal) MP for Avalon, announces he accepts the findings of an investigation into his misconduct and will serve out his term as an independent.[66]
March 31, 2015: James Lunney, Conservative MP for Nanaimo—Alberni leaves the Conservative Party caucus to sit as an independent, citing concerns about religious freedom.[68]
June 9, 2015: Bloc splits the position of leader into two different positions : Mario Beaulieu remains as president (internal organisation), while Gilles Duceppe comes back as political leader only. The decision has later been approved in a special congress on July 1, with 99.7% in favour.
September 28, 2015: Deadlines for candidates to submit their nomination.
September 30, 2015: Confirmed list of candidates is published.
October 9–12, 2015: Advance polls were open. An estimated record of 3.6 million electors cast their ballot, a 71% increase over the previous 2011 election.[70] This turnout was superseded during the 2019 general election.
October 19, 2015: Scheduled polling day. The Governor-in-Council retains constitutional authority, subject to section 4(1) of the Constitution Act, 1982, to set an earlier election date.