The Public Service of Canada (known as the Civil Service of Canada prior to 1967) is the civilian workforce of the Government of Canada's departments, agencies, and other public bodies.

While the Government of Canada has employed civil servants to support its functions since Confederation in 1867, positions were initially filled through patronage until 1908, when the Laurier government enacted the Public Service Amendment Act, which established the merit-based appointment system which governs hiring within the federal public service today. As of 2020, the Public Service employs 319,601 people, and is Canada's largest single employer.

There are 137 distinct organizations within the Public Service, including 23 ministerial (line) departments, 3 service agencies, 17 departmental corporations, 50 departmental agencies, 12 special operating agencies, and 6 agents of Parliament. While Crown corporations are owned by the federal government, employees are generally not considered to be public servants and are instead employed by the corporation itself. Over 40 per cent of the Public Service of Canada is located in the National Capital Region, many public servants are situated at approximately 1,600 locations throughout Canada.

Public service organizations are divided into the Core Public Administration (CPA), defined as organizations listed under schedules I and IV in the Financial Administration Act (FAA), primarily consisting of ministerial departments and departmental agencies such as Global Affairs Canada and the Correctional Service of Canada, and Separate Agencies, which are listed under schedule V of the FAA, which includes organizations such as the Canada Revenue Agency and Parks Canada.

The clerk of the Privy Council is the head of the Public Service, and is the most senior public servant within the Canadian federal government. Michael Sabia has served as the clerk since July 7, 2025.

Prior to introduction of responsible government in 1848, the Province of Canada, then a British colonial possession lacked an organized civil service. Positions in the colonial administration were then largely filled through patronage, with appointments almost exclusively controlled by the sitting governor, often under the advisement of members of the ruling Family Compact, who would recommend the selection of candidates who were supportive of the ruling elite. As such, government officials would be appointed for life, often leading to instances where members of the same family would occupy a position for several generations.

While the introduction of responsible government, which conferred more authority toward the popularly-elected Assembly to oversee appointments to the civil services, successive governments continued the practice of drawing appointees to non-political (civil) positions. Unlike the American spoils system, political appointees did not typically resign when a new government was sworn in, which created friction between Cabinet and civil servants as governments changed.

To address the persistence of patronage appointments, Parliament enacted legislation in 1857 to establish a Board of Examiners for the Civil Service. The role of the board would be to examine "candidates for employment in the Civil Service" and "to grant certificates of qualification to those found to possess the moral character and fitness required for service".