The fuddle duddle incident in Canadian political history occurred on February 16, 1971 when Prime Minister of Canada Pierre Elliott Trudeau was alleged to have spoken or at least mouthed unparliamentary language in the House of Commons, causing a minor scandal. Trudeau mentioned the words "fuddle duddle" in an ambiguous answer to questions about what he may or may not have said in Parliament.

In February 1971, opposition MPs accused Trudeau of having mouthed the words "fuck off" at them in the House of Commons. When pressed by television reporters on the matter, Trudeau would only freely admit having moved his lips, answering the question, "What were you thinking, when you moved your lips?" by rhetorically asking in return "What is the nature of your thoughts, gentlemen, when you say 'fuddle duddle' or something like that?" Thus, it remained unclear what Trudeau actually mouthed.

There is a popular misconception that "fuddle duddle" was coined as a euphemism by the Hansard reporter who prepared the official transcript of Trudeau's words for that parliamentary session. However, Hansard did not record the exchange. In any case, Trudeau used it during a media scrum in the immediate aftermath of the parliamentary incident itself, leaving little time for a Hansard transcript to be consulted or even prepared.

Joseph Philippe Pierre Yves Elliott Trudeau CC, CH, PC, QC, FSRC ( /truːˈdoʊ/; French pronunciation: [tʁydo]; October 18, 1919 – September 28, 2000), usually known as Pierre Trudeau or Pierre Elliott Trudeau, was the 15th Prime Minister of Canada from April 20, 1968 to June 4, 1979, and again from March 3, 1980 to June 30, 1984.

Trudeau began his political career campaigning for socialist ideals, but he eventually joined the Liberal Party of Canada when he entered federal politics in the 1960s. He was appointed as Lester Pearson's Parliamentary Secretary, and later became his Minister of Justice. From his base in Montreal, Trudeau took control of the Liberal Party and became a charismatic leader, inspiring "Trudeaumania". From the late 1960s until the mid-1980s, he dominated the Canadian political scene and aroused passionate reactions. "Reason before passion" was his personal motto. He retired from politics in 1984, and John Turner succeeded him as Prime Minister.

Admirers praise the force of Trudeau's intellect and they salute his political acumen in preserving national unity against Quebec separatists, suppressing a violent revolt, and establishing the Charter of Rights and Freedoms within Canada's constitution. Critics accuse him of arrogance, economic mismanagement, and unduly favouring the federal government relative to the provinces, especially in trying to control the oil wealth of the Prairies.