The Cayley-Galt Tariff of 1858 was the first protective tariff in Canadian history. It imposed import duties on imported manufactured goods of 20% and a duty on 10% on partially manufactured goods in an attempt to spur domestic manufacturing industries.

The tariff caused immediate resentment among both the British and Americans. The anger of the Americans played an important role in their 1866 repeal of the Reciprocity Treaty that had lead to free trade in natural resources. The tariff was only a foretaste of the much more complete system of protection set up under the National Policy of 1871.