The Official Opposition Shadow Cabinet in Canada is composed of members of the main Opposition party responsible for holding the Government to account and for developing and disseminating the party's policy positions.

[1] Layton went on a leave of absence beginning July 28, 2011, in order to fight a new cancer and Nycole Turmel was appointed interim leader.

Thomas Mulcair was elected leader of the NDP, and by extension Leader of the Opposition, at a leadership election held on March 24, 2012, and reshuffled the Shadow Cabinet on April 19, 2012.

Craig Scott replaced Joe Comartin as Democratic Reform critic after the latter became Deputy Speaker in September 2012.

On January 17, 2013, Mulcair replaced Hoang Mai with Murray Rankin as National Revenue critic.