Rathika Sitsabaiesan (born December 23, 1981) is a Canadian politician and activist of Sri Lankan origin.
She was formerly part of the New Democratic Party and represented Scarborough—Rouge River in the House of Commons of Canada as a Member of Parliament between 2011 and 2015.
She was the first Tamil to be elected to the Canadian federal parliament as well the first woman and first visible minority to be elected as Member of Parliament for Scarborough—Rouge River.
She was also the youngest Member of Parliament in the Greater Toronto Area.In 2016, Sitsabaiesan switched parties in order to seek the Ontario Liberal Party nomination for the vacant provincial Scarborough—Rouge River seat.
Piragal Thiru defeated Sitsabaiesan for the Liberal nomination on June 5, 2016.