The Workers' Party called for a No vote against the Treaty of Lisbon in both the June 2008 referendum, in which the proposal was defeated, and the October 2009 referendum, in which the proposal was approved. It was the only left-wing party to campaign for a No vote in the 2013 Seanad Abolition referendum. It called for a Yes vote in the marriage equality referendum in 2015. The party supported Brexit in the 2016 referendum.