Paul Mercier (14 February 1888 – 10 August 1943) was a Liberal party member of the House of Commons of Canada. He was born in Montreal, Quebec and became a lawyer.

Mercier attended school at Montcalm, then Sainte-Therese College and Université Laval. He was appointed as King's Counsel in 1922.^[1]

He was first elected to Parliament at the Westmount—St. Henri riding in the 1921 general election. After riding boundary changes in 1924, Mercier was re-elected at the new St. Henri electoral district in the 1925 federal election, then re-elected there in 1926, 1930 and 1935 (in 1933, the riding's English name became "St. Henry").

On 29 November 1937, Mercier accepted an appointment to become a Montreal region Circuit Court judge, leaving the House of Commons before completing his term in the 18th Canadian Parliament.