Voters in the Montreal riding of Gouin will head to the polls in a byelection on May 29.
Gouin was previously held by former Québec Solidaire founder and longtime activist Françoise David, who decided to leave politics in January.
Quebec Premier Philippe Couillard made the announcement on Wednesday.
Québec Solidaire candidate and former student leader Gabriel Nadeau-Dubois will face off against the Quebec Liberal Party's Jonathan Marleau, the former president of the party's youth wing.
The Parti Québécois has chosen not to present a candidate.