Honoré Mercier Jr. KC (20 March 1875 – 19 June 1937) was a member of the Legislative Assembly of Quebec.

Mercier was born in Saint-Hyacinthe, Quebec, and attended Collège Sainte-Marie and Université Laval law school.

Mercier was a lawyer prior to his political career.

However, he was then elected in a 1908 by-election, and remained in the Legislative Assembly until 1936, when he did not run for re-election.

He served in numerous Cabinet posts under Premiers Lomer Gouin and Louis-Alexandre Taschereau: Besides his legal practice, Mercier was a member, director and headed of various organizations in Quebec: Gérald Fauteux was his nephew.