While the House of Commons is also known as Parliament, Parliament itself is a two-tiered, or bicameral, body. The other part of Parliament is the Senate. Distinct from the House of Commons, which is elected by the people of Canada, the Senate is composed of people appointed by the Governor General on the advice of the Prime Minister. The role of the Senate is as a sober second opinion that considers legislation passed by the House of Commons. It has 105 members.

Of these 105 seats, 24 must come from Ontario, 24 from Québec, 10 from Nova Scotia, 10 from New Brunswick, 4 from Prince Edward Island, 6 from Newfoundland, 6 from Manitoba, 6 from Saskatchewan, 6 from Alberta, 6 from British Columbia, and one from each of the Yukon Territory, the Northwest Territories, and Nunavut. There is also provision for 4 or 8 extra senators. Appointment is now until a senator reaches 75 years of age.

Senate must pass all bills of legislation passed by the House of Commons before they go forward to the Governor General to be signed into law.