The tariffs cover steel and aluminum products, as well as imports of goods such as ketchup and playing cards
The Canadian government has said it 'had no choice' but to announce retaliatory tariffs against the US.
It comes amid the escalating trade war between the US and other countries, with the EU having already introduced a range of countermeasures to the Trump administration's steel and aluminum tariffs.
The tariffs cover $16.6 billion of imports from the US, while the Canadian government also is providing "$2 billion to defend and protect the interests of Canadian workers and businesses in the steel, aluminum and manufacturing industries".
As well as tariffs on US steel and aluminum, the Canadian restrictions hit dozens of other US imports - ranging from tomato ketchup and whiskies to sleeping bags and playing cards.
The tariffs will come into force tomorrow, July 1st.
In a statement, Chrystia Freeland - the Canadian Minister of Foreign Affairs called the US tariffs "protectionist and illegal", and said her country's response is its strongest trade action since World War 2.
She argued: "The idea that Canada might constitute a threat to American national security - the legal pretext invoked by our neighbours to impose these tariffs on Canadian steel and aluminum exports - is not only absurd, it's hurtful.
"Canada has no choice but to retaliate with a measured, perfectly reciprocal dollar-for-dollar response - and that is what we are doing."
She added: "Canada's approach is, and will be, this: we will not escalate, and we will not back down."
Canadian Prime Minister Justin Trudeau is said to have called Donald Trump to inform him of the new tariffs.
A readout of the call quoted by CBC News explains: "As he has said in past conversations and in public, the Prime Minister conveyed that Canada has had no choice but to announce reciprocal countermeasures to the steel and aluminum tariffs that the United States imposed on June 1, 2018."
Meanwhile, the General Motors company has warned the Trump administration that any import tariffs on cars and vehicle parts could cost US jobs.
Last month, President Trump ordered an investigation into automobile imports to see if they 'threaten national security'.
The US President has publicly threatened the EU with a 20% tariff on all cars coming into the US:
Based on the Tariffs and Trade Barriers long placed on the U.S. & its great companies and workers by the European Union, if these Tariffs and Barriers are not soon broken down and removed, we will be placing a 20% Tariff on all of their cars coming into the U.S. Build them here!— Donald J. Trump (@realDonaldTrump) June 23, 2018
In a document submitted to regulators, General Motors argued: "If import tariffs on automobiles are not tailored to specifically advance the objectives of the economic and national security goals of the United States, increased import tariffs could lead to a smaller [General Motors], a reduced presence at home and abroad for this iconic American company, and risk less - not more US jobs.
"Combined with the other trade actions currently being pursued by the U.S. Government - namely the 232 Steel and Aluminum tariffs and the Section 301 tariffs against Chinese imports - the threat of additional tariffs on automobile imports could be detrimental to our company."