| 1918 | November 11 | Armistice signed ending World War I - of the 660,000 man Canadian Expeditionary Force 60,000 were killed in action and 173,00 wounded. |
| November 14 | The United Farmers of Ontario take control of the provincial legislature. Premier Ernest Drury forms a UFO majority government. |
| 1919 | February 17 | Sir Wilfred Laurier, former Prime Minister, dies in Ottawa at age 78. |
| May 15 | The Winnipeg Trades and Labour Council call a General Strike that begins in the building trades and quickly spreads to other sectors of economy. Police, fire and telephone services are crippled. |
| May 22 | The House of Commons adopts the Nickel Resolution ending the award of British knighthoods and titles of nobility to Canadians. |
| June 17 | Eight leaders of the Winnipeg General Strike and four suspected Bolsheviks are arrested. |
| June 21 | Two people are killed when police breakup a peaceful march by Winnipeg strikers. |
| June 25 | The Winnipeg General Strike is called off by its organizers. |
| June 28 | The Paris Peace Conference ends. Prime Minister Borden signs the Treaty of Versailles for Canada. |
| August 7 | Captain Ernest Hoy completes the first airplane flight over the Canadian Rockies. Hoy's Curtiss Jenny covers the route from Vancouver to Calgary in 17 hours. |
| September | The Department of Naval Service issues Canada's first broadcasting license to the Marconi Wireless Telegraph Company's station XWA in Montreal. |
| 1920 | January 10 | The League of Nations convenes for the first time. Canada is a charter member. |
| February 1 | The Dominion Police Force and Royal Northwest Mounted Police merge to form the Royal Canadian Mounted Police. |
| May 7 | The Group of Seven, landscape artists, open their first exhibition at the Art Gallery of Ontario in Toronto. |
| July 10 | Arthur Meighen succeeds the retiring Sir Robert Laird Borden as Prime Minister. |
| October 25 | Voters approve the continuation of Prohibition in Alberta, Manitoba, Saskatchewan and Nova Scotia referendums. |
| December 1 | Immigration is restricted to individuals possessing at least $250 upon entry. |
| December 4 | The University of Toronto Varsity Blues defeat the Toronto Argonauts 16 to 3 in the first Grey Cup football match played since 1915. |
| December | Imperial Oil announces the discovery of petroleum deposits near Fort Norman in the Northwest Territories. |
| | The University of Montreal is founded. |
| 1921 | May | The Communist Party of Canada is founded at clandestine meeting in a barn on the outskirts of Guelph, Ontario. |
| June 1 | Census returns place the population of Canada at 8,788,483. |
| Summer | Canada leads the opposition to renewal of the Anglo-Japanese Alliance at the Imperial Conference in London. |
| August 11 | Sir Julian Byng, Viscount Byng of Vimy, sworn in as Governor General. Byng commanded the Canadian Expeditionary Force when it captured Vimy Ridge. |
| August 13 | The United Farmers of Albert form a provincial government under Premier Herbert Greenfield. |
| August | Franklin D. Roosevelt contracts polio while vacationing at his summer home on Campobello Island, New Brunswick. |
| October | The Canadian Battlefields Memorial Commission selects Toronto sculptor Walter S. Allward's design for the Canadian national memorial at Vimy Ridge. |
| October 24 | Bluenose of Lunenburg, Nova Scotia defeats Elsie of Gloucester, Massachusetts to win the International Fisherman's Trophy race for schooners. |
| December 3 | The Toronto Argonauts defeat the Edmonton Eskimos in the first East-West Grey Cup football championship. |
| December 6 | General Election - William Lyon Mackenzie King's Liberal Party ousts the Conservative Government of Prime Minister Arthur Meighen. |
| | Distribution of seats in the new House of Commons: Liberals 117, Progressives 65, Conservatives 50 and Labour 2 |
| December 6 | Agnes Campbell MacPhail is the first woman elected to the House of Commons. MacPhail represents the district of Grey South East in Ontario. |
| December 29 | Liberal Party leader William Lyon MacKenzie King becomes Prime Minister. |
| 1922 | January 1 | British Columbia drivers switch from keeping to the left to keeping right. |
| February 11 | Doctors Frederick Banting, Charles Best, James Collip and J.J.R. Macleod announce the discovery of insulin as a treatment for diabetes. |
| April | The Ministry of Marine and Fisheries issues licenses for 20 radio broadcasting stations. |
| August 2 | Alexander Graham Bell, inventor of the telephone, dies at Baddeck, Nova Scotia. |
| August 16 | The militia is called out to end a coal miners strike in Cape Breton, Nova Scotia. |
| September | Canada refuses to support British intervention in Turkey following the Chanak Affair. |
| September 27 | The First French language radio station in North America, CKAC Montreal, goes on air |
| | The United States replaces Great Britain as the largest foreign investor in Canada. |
| 1923 | January 4 | George H. Murray resigns after serving a record 27 years as Premier of Nova Scotia. |
| January 31 | The Royal Canadian Navy Volunteer Reserve is created by an Order in Council. |
| March 2 | Canada signs a Treaty for the Protection of the Pacific Halibut Fishery with the United States without recourse to the British Ambassador in Washington. |
| March 22 | Foster Hewitt broadcasts his first hockey game over station CFCA Toronto. |
| October 25 | The Nobel Prize for Medicine is awarded to Doctors Frederick Banting and J.J.R. Macleod for their work in discovering insulin. |
| 1924 | March 17 | The Canadian Government declares that it will not consider decisions of the Imperial Conference binding without a vote of ratification by the Canadian Parliament. |
| April 1 | The Royal Canadian Air Force is founded. |
| May 10 | Prohibition ends in Alberta after 8 years. |
| June 27 | Methodist, Presbyterian and Congregational churches merge to form the United Church of Canada. |
| June 29 | Canada's first postal workers strike ends after 10 days. |
| October 23 | A provincial referendum upholds the Ontario Temperance Act of 1916 by a 50,000 vote majority. |
| October 29 | Doukhobor leader Peter V. Verigin and 8 others are killed when a bomb explodes on passenger train near Farron, British Columbia. |
| November 29 | The Montreal Forum opens. Les Canadiens defeat the Toronto Maple Leafs 7 to 1 in a National Hockey League match. |
| 1925 | June 23 | Canada's highest mountain peak, Mount Logan in the Yukon Territory's Saint Elias Range, is conquered for the first time. Seven climbers reach the summit of the 5959m high peak. |
| October 29 | General Election - MacKenzie King's Liberals finish second to the Conservatives but remain in power with Progressive support. |
| | Distribution of seats in the new House of Commons: Conservatives 118, Liberals 101, Progressives 23, Labour 2 and Independents 1 |
| 1926 | January 15 | Progressives join Liberals to defeat a Conservative "no confidence" resolution in the House of Commons. |
| April 6 | The Montreal Maroons win the Stanley Cup with a 2 to 0 win over the Victoria Cougars at the Montreal Forum. |
| June 28 | The Liberal Government of Prime Minister MacKenzie King resigns following reports of corruption in the Customs Service. Governor General Byng refuses King's request for a dissolution of the Commons and asks Arthur Meighen to form a Government. |
| June 29 | Conservative Arthur Meighen is sworn in as Prime Minister but loses a vote of confidence four days later. |
| July 1 | Canada returns to the Gold Standard. |
| September 14 | General Election for a new House of Commons: Liberals 119, |
| | Conservatives 91, Liberal/Progressives 11,United Farmers of Alberta 11, Progressives 8, Labour 3 and Independents 2 |
| September 25 | William Lyon MacKenzie King sworn in as head of a Liberal majority government. |
| October 2 | Sir Freeman Freeman-Thomas, Marquess of Willingdon is sworn in as Governor General. The Governor General henceforth represents the Crown and not the British Government and acts on the advice of his Canadian ministers. |
| November 10 | Vincent Massey is appointed as first Canadian Minister to Washington. |
| 1927 | February | William Phillips is appointed as first American Minister to Canada. |
| June 6 | The Ku Klux Klan stages its largest rally ever held in Canada at Moose Jaw, Saskatchewan. The Klan boasts 125 chapters in the province at its peak. |
| July 1 | 60th Anniversary of the formation of the Canadian Confederation - The Prince of Wales, Prince George and Prime Minister Stanley Baldwin of Great Britain visit Ottawa for the dedication of the Parliament Building's Peace Tower. |
| August 7 | The Peace Bridge spanning the Niagara River between Fort Erie, Ontario and Buffalo, New York dedicated in the presence of the Prince of Wales, Prince George, Prime Ministers King and Baldwin, Vice President Dawes, Secretary of State Kellogg and Governor Smith. |
| September 15 | Canada is elected to a seat on the League of Nations Council. |
| 1928 | January 10 | Philippe Roy is appointed first Canadian Minister to France. |
| April 24 | The Supreme Court of Canada issues a unanimous ruling that women are not persons under Section 24 of the British North America Act and thus ineligible for appointment to the Senate. |
| | The Canadian Government pays Otto Sverdrup $67,000 for his maps, reports and expedition diaries to secure its claims to high Arctic islands discovered by the Norwegian explorer at the turn of the century. |
| | Herbert Marler is appointed first Canadian ambassador to Japan. |
| 1929 | January 2 | A convention on the preservation of Niagara Falls between the United States and Canada is ratified by the Canadian Parliament. |
| April 9 | The Canadian register schooner I'm Alone is sunk in the Gulf of Mexico by a United States Coast Guard prohibition patrol. Canada lodges a diplomatic protest. The United States agrees to arbitrate the dispute. |
| July 18 | Prince Edward Island votes to continue Prohibition. |
| September 9 | Saskatchewan General Elections are won by the Conservatives with the support of the Ku Klux Klan for their platform opposing French language education and immigration. |
| September 10 | The Canadian National Railway opens a branch line to Churchill, Manitoba on Hudson's Bay. |
| October 18 | The Privy Council overturns the Supreme Court of Canada's ruling that women are not persons under the law and thus ineligible for appointment to the Senate. |
| October | Nova Scotia voters repeal Prohibition. |
| November 18 | A magnitude 7.2 Richter Scale earthquake centered in the Grand Banks severs 12 transatlantic cables and causes minor damage on Cape Breton Island. |
| 1930 | February 5 | Cairine Wilson of Ontario becomes the first woman to sit in the Canadian Senate. |
| | Gilbert Labine of Eldorado Gold Mines Limited discovers uranium and radium bearing ores on the shore of Great Bear near Port Radium, Northwest Territories. |
| July 28 | General Election for a new House of Commons - Richard Bennett's Conservatives sweep MacKenzie King from power. |
| | Conservatives 139, Liberals 89, Progressives 12, Labour 3 and Independents 2 |
| August 7 | Conservative Richard Bedford Bennett becomes Prime Minister. |
| August 9 | Percy Williams sets the world record for 100 meter dash at 10.33 seconds. |
| August 15 | Immigration of Europeans is further restricted. |
| August 16 | The first British Empire Games open in Hamilton, Ontario. |
| October 1 | The Federal Government turns control of natural resources over to the provinces of Alberta, Saskatchewan and Manitoba. |
| 1931 | April 4 | Sir Vere Brabazon Ponsonby, Earl of Bessborough sworn in as Governor General. The ceremony is broadcast over radio for the first time. |
| June 1 | Census returns place Canada's population at 10,376,796. |
| September 29 | Striking coal miners clash with police in Estevan, Saskatchewan. Three strikers are killed and 23 are injured. |
| October 31 | Gold export is banned by Order in Council. The Canadian dollar plunges in value to 80 cents American. |
| November | An Ontario court sentences 8 leaders of the outlawed Communist Party to prison. |
| November 12 | Toronto's Maple Leaf Gardens opens. The Leafs lose to the Chicago Blackhawks 2 to 1. |
| December 11 | The Statute of Westminster grants dominions full legal independence. Canada requests that Westminster retain the right to amend the British North America Act. |
| December 31 | Albert Johnson aka "The Mad Trapper of Rat River" shoots and kills an RCMP constable investigating trapline poaching near Fort MacPherson, Northwest Territories. |
| | British Columbia disenfranchises members of pacifist religious sects exempted from military service (Doukhobors, Mennonites and Hutterites) and extends the franchise to Japanese Canadian veterans of World War I. |
| 1932 | February 17 | The Mad Trapper of Rat River (Albert Johnson) is tracked down by bush pilot Wop May and killed in a shoot out with the RCMP. Johnson eluded police for 48 days in -40° C temperatures. |
| May 4 | Tent towns spring up along the banks of the Red Deer River in Alberta following the discovery of gold. |
| May 24 | The Canadian Broadcasting Corporation is created by Act of Parliament. |
| July 18 | The United States and Canada sign the Saint Lawrence Seaway Agreement. |
| July 21 | The Ottawa Conference on Imperial Economic Co-operation opens. |
| August 1 | The Co-operative Commonwealth Federation is formed a conference of labor leaders in Calgary. The CCF's program calls for socialisation of health care, financial institutions, utilities and natural resources. |
| September 30 | Agricultural workers abandon crops in the field after Prime Minister Bennett cancels an agreement under which unemployed workers are allowed to ride in empty freight cars for free. |
| | Eldorado Gold Mines Limited begins mining the Port Radium deposits and builds a refining plant at Port Hope, Ontario. |
| 1933 | | The first delivery of Canadian radium for use in cancer treatment is made. Uranium, a byproduct of the radium refining process, is sold as a coloring agent for glass and ceramics. |
| April 10 | The redemption of bank notes for gold is suspended by an Order in Council. |
| May 23 | Parliament passes the Canadian National-Canadian Pacific Railway Act requiring the two corporations to cooperate in providing rail service to the country. |
| June 18 | American President Franklin D. Roosevelt visits his summer home on Campobello Island, New Brunswick for the first time in twelve years. |
| July 19 | The Cooperative Commonwealth Federation issues its Regina Manifesto, "We aim to replace the present capitalist system, with its inherent injustice and inhumanity, by a social order from which the domination and exploitation of one class by another will be eliminated." |
| August 1 | The Mayor of Toronto bans the display of swastikas within the city. |
| November 2 | The Cooperative Commonwealth Federation finishes second in elections to the British Columbia legislature with 31.5% of the vote to become the official opposition. |
| 1934 | April | The Ottawa Senators, seven time Stanley Cup champions, play their last National Hockey League game. Major league ice hockey absents itself from Canada's capital for the next 58 years. |
| April 6 | Major C.H. Douglas addresses the Alberta legislature on his theory of Social Credit. |
| April 14 | The Alberta Legislature votes to abolish the office of Lieutenant Governor (King's Representative) and to convert the official residence, Government House, into a tuberculosis sanitarium. The motion is later rescinded. |
| May 28 | Cecile, Yvonne, Emile, Annette and Marie the world's first known surviving quintuplets are born to Oliva and Elzire Dionne at Callander, Ontario. |
| June 18 | The Liberal Party led by Mitchell Hepburn ousts the Conservatives as the Government of Ontario. |
| July 3 | The Bank of Canada is created by Act of Parliament. |
| August 29 | A crowd of 300,000 gathers in Montreal's Lafontaine Park to celebrate the 400th Anniversary of Jacques Cartier's discovery of Canada. |
| 1935 | January 9 | An arbitration ruling in the case of the rumrunner I'm Alone requires the United States to issue a formal apology, pay $25,000 to the Canadian Government and $25,666 to the Captain and crew of the ship. |
| February 21 | A reindeer herd is transplanted from Kotzebue, Alaska to the MacKenzie River delta in the Northwest Territories to provide income for local Inuit. |
| March 28 | Francis Rattenbury, architect of the British Columbia legislative buildings and Victoria's Empress Hotel dies. |
| May 20 | Doukhobor leader Peter P. Verigin, citing religious persecution and fears of Fascism, declares his intention to lead his sect out of Canada to a new colony possibly in Paraguay. |
| June 3 | The "On to Ottawa" trek begins when 1000 men from relief camps in British Columbia seize railcars intending to reach the capital and demand the Government provide work programs. Their numbers grow to 2000+ by the time they reach Regina where the trains are stopped. Eight leaders go to a meeting with Prime Minister Bennett while the rest camp in the Regina Exhibition Grounds. |
| July 1 | Regina Police and RCMP attempt to arrest On to Ottawa trek leaders at a rally in Regina. One constable is killed in the ensuing riot. |
| July 5 | The Government agrees to provide On to Ottawa trekkers remaining in Regina with rail tickets home. |
| August 22 | The Social Credit Party led by William Aberhart wins 56 of 63 seats in the Alberta legislature ousting the scandal plagued United Farmers of Alberta administration. |
| October 14 | General Election - MacKenzie King's Liberals are swept back to power. |
| | Distribution of seats in the new House of Commons: Liberals 171, Conservatives 40, Social Credit 17, Independent Liberals 8, CCF 7, Reconstruction 1 and United Farmer's of Ontario 1 |
| October 23 | William Lyon MacKenzie King becomes Prime Minister for a third time. |
| November 2 | Sir John Buchan, Baron Tweedsmuir sworn in as Governor General of Canada. |
| November 7 | Maurice Duplessis is elected to head l'Union Nationale, a Quebec provincial party composed of Conservatives and dissident Liberals. |
| November 15 | Canada signs a reciprocal tariff agreement with the United States. |
| 1936 | March 25 | The longest game in the history of the National Hockey League is played at the Forum in Montreal. The Maroons defeat the Detroit Redwings 1 to 0 on a goal by Mud Bruneteau at 16:30 in the 6th overtime period. |
| June 16 | The Federal Government announces that the economy has recovered sufficiently to allow closure of work camps for unemployed single men. |
| June 17 | The Supreme Court of Canada declares the Natural Product Marketing Act and several other cornerstones of Prime Minister King's "New Deal" including compulsory unemployment insurance unconstitutional. |
| July 26 | King Edward VIII unveils the Canadian National Memorial at Vimy Ridge before a crowd 100,000 including former Prime Minister Robert Borden, French President Albert Lebrun and 6000 veterans of the Canadian Expeditionary Force, "For this glorious monument crowning the hill of Vimy is now and for all time part of Canada. Though the mortal remains of Canada's sons lie far from home, yet here where we now stand in ancient Artois their immortal memory is hallowed upon soil that is as surely Canada's as any acre within her nine provinces. By a gesture which all can understand, but soldiers especially, the laws of France have decreed that here Canada shall stand forever." |
| August 5 | Social Credit government issues first Albert Prosperity Bonds |
| August 17 | L'Union Nationale wins the General Election in Quebec with 57% of the popular vote and 76 seats in the Quebec National Assembly against 39% of the vote and 14 seats for the Liberal opposition. Maurice Duplessis becomes Premier. |
| 1937 | January 28 | The Privy Council upholds the Supreme Court of Canada in declaring King’s "New Deal" legislation unconstitutional. March 9 |
| | Banks refuse to cash Alberta Government relief checks. |
| March 11 | A funeral for Montreal Canadiens hockey player Howie Morenz, who died of injuries sustained in a game six weeks early, is held at center ice of the Montreal Forum with 50,000 fans in attendance. |
| March 24 | The Quebec National Assembly approves An Act Respecting Communistic Propaganda. The "Padlock Law" empowers Quebec's Attorney General and police to close any property being used for the purpose of propagating Communism but does not define Communism. |
| April 10 | Parliament passes the Foreign Enlistments Act to bar Canadians from joining the armed forces of non-British countries. 1,239 Canadians led by Dr. Norman Bethune defy the ban to fight on the Republican side of the Spanish Civil War as the Mackenzie-Papineau Battalion of the International Brigade. |
| April 26 | Premier Thomas Patullo announces agreement with the Federal Government for British Columbia to annex the Yukon Territory. The Yukon Territorial Council opposes the measure. |
| April 28 | General Motors agrees to a contract with the United Automobile Workers ending a 15 day strike at its Oshawa, Ontario plant. |
| | Premier Hepburn denounces the Congress of Industrial Organizations as foreign agitators and turns the province's labor leaders against the Liberal Party. |
| June 10 | Sir Robert Laird Borden, former Prime Minister, dies in Ottawa. |
| June 29 | Armand Bombardier is granted patent for the snowmobile. |
| June 30 | Prime Minister King ends a visit to Berlin with praise Hitler’s for promotion of "understanding, friendship and goodwill”. September 30 |
| | President Franklin Roosevelt is greeted by 20,000 well wishers on visit to Victoria, British Columbia. |
| | The Social Credit Government of Albert enacts the Alberta Press Act requiring newspapers to disclose their sources to the Alberta Social Credit Board and to publish the Government's rebuttal to any criticism of its policies. |
| 1938 | January 27 | Honeymoon Bridge at Niagara Falls is destroyed by an ice jam. |
| | Radium production at Eldorado Gold Mines' Port Hope refinery reaches 2.5 grams per month. |
| March 4 | The Supreme Court of Canada declares the Alberta Social Credit Act, The Alberta Press Act and provincial laws regulating credit and taxing banks unconstitutional. |
| April 13 | Archibald Belamey who wrote numerous books on the life of the Prairie Indians and the need for conserving Canada's natural resources under the nom de plume Grey Owl dies. |
| June 7 | Chartered banks announce a mass closure of rural branches in attempt to roll back Alberta provincial legislation enacted to control bank profits. |
| June 22 | The Montreal Maroons hockey club withdraws from the National Hockey League. |
| July 8 | The Privy Council upholds the Supreme Court in overturning the Alberta Press Act. The Edmonton Journal is awarded the Pulitzer Prize for its defense of press freedom. |
| July | Fascist splinter groups form the National Unity Party under the leadership of Adrien Arcand. |
| August | President Roosevelt meets with Prime Minister King in Kingston, Ontario and announces that the United States would, "not stand idly by if domination of Canadian soil is threatened by any other empire." |
| 1939 | May 17 | King George VI and Queen Elizabeth arrive in Quebec City to begin a month long tour of Canada, the first visit to Canada by a reigning monarch. |
| June 8 | Canada refuses to admit 900 Jewish refugees on the liner Saint Louis. |
| June 15 | King George VI and Queen Elizabeth sail from Halifax for Great Britain. |
| July 7 | The Vatican removes L'Action Francais from the Index of Prohibited Books after Quebec Archbishop Rodrigue Villeneuve intervenes in behalf of the publication. |
| August 25 | Militia units are mobilized to protect government property and man coastal fortifications. |
| August 26 | Merchant ships are prohibited from leaving Canadian ports without authorization of the Royal Canadian Navy. |
| September 1 | Princess Patricia's Canadian Light Infantry, the Royal 22e Regiment, the Royal Regiment of Canada and 14 militia regiments are mobilized. |
| September 3 | The SS Athenia is sunk en route to Montreal without warning by U-30, 250 miles west of Ireland. |
