The Naval Service Act was a statute of the Parliament of Canada, enacted in 1910. The Act was put forward by the Liberal government of Prime Minister Sir Wilfrid Laurier to establish a Canadian navy. Prior to the passage of the Act, Canada did not have a navy of its own, being dependent on the British Royal Navy for maritime defence. The Act intended to provide Canada with a separate naval force, but one that, if needed, could be placed under British control during a time of war. French-Canadian nationalists and British-Canadian imperialists both opposed the Act, although for different reasons. The controversy of the naval question eventually contributed to the defeat of Laurier's government in the federal election of 1911. The new Conservative government, led by Prime Minister Sir Robert Borden, instead proposed building three battleships or cruisers, to be put at the service of the British Navy.

After the passage of the Naval Service Act, the Naval Service was established on May 4, 1910. the initiation of this act was a direct response to the naval arms race that was happening between Britain and Germany. Also, Britain supported this act because it was worried over the expansion of the German Navy. By the end of 1910, the Naval Service's first vessels were inaugurated, two former British Royal Navy vessels. The act also established the Naval Reserve and the Naval College. The Naval Service became known as the Royal Canadian Navy in 1911.

The Naval Service Act remained in force, with amendments and modifications, until being repealed and replaced by the National Defence Act in 1950.