The Oath of Citizenship, or Citizenship Oath (in French: serment de citoyenneté), is a statement recited and signed by those who apply to become citizens of Canada. Administered at a ceremony presided over by a designated official, the oath is a promise or declaration of fealty to the Canadian monarch and a promise to abide by Canada's laws and uphold the duties of a Canadian citizen; upon signing the oath, citizenship is granted to the applicant.
The vow's roots lie in the oath of allegiance taken in the United Kingdom, the modern form of which was implemented in 1689 by King William II and III and Queen Mary II and was inherited by and used in Canada prior to 1947. With the enactment of the Citizenship Act that year, the Canadian Oath of Citizenship was established. Proposals for modification of the oath have surfaced from time to time, including removing references to the sovereign, adding loyalty to societal principles, and/or adding specific mention to Canada. However, it is maintained within Canada's legal system "that the oath to the Queen is in fact an oath to a domestic institution that represents egalitarian governance and the rule of law". Consequently, it has only been modified once, in 1977.
Prior to 1947, Canadian law continued to refer to Canadian nationals as British subjects, despite the country being since 1931 independent from the United Kingdom. As the country shared the same person as its sovereign with the other countries of the Commonwealth, people immigrating from those states were not required to recite any oath upon immigration to Canada; those coming from a non-Commonwealth country would take the Oath of Allegiance. When India became a republic in 1950, however, the Commonwealth contained countries that did not recognize the monarch shared amongst the Commonwealth realms as their own, though still regarding that individual as Head of the Commonwealth.