Significant dates in labour history.
- December 01 - W. A. Boyle was born; the Federated Ship Painters and Dockers Union was dissolved
- December 02 - The Professional Footballers' Association was founded
- December 03 - Tom Mooney died
- December 04 - The American Federation of Labor and Congress of Industrial Organizations were dissolved; George L. Berry died; the 2007 South Africa miners' strike occurred
- December 05 - The American Federation of Labor and Congress of Industrial Organizations merged to form the AFL–CIO
- December 06 - Santa Marta massacre occurred in Colombia in 1928; the Bituminous coal strike of 1977–78 began in the U.S.; the Socialist Trade and Labor Alliance was founded
- December 07 - The International Union of Operating Engineers was founded; the Fiji Teachers Union was founded; Vere Bird was born
- December 08 - Federation of Organized Trades and Labor Unions disbanded to from the American Federation of Labor; Anil Moonesinghe died; Bernice Fisher was born
- December 09 - Thomas Hepburn died; the International Federation of Building and Wood Workers was dissolved; Bob Hawke was born; Selig Perlman was born; Pablo Iglesias died
- December 10 - Jean Maitron is born; the American Federation of Teachers won its first collective bargaining election
- December 11 - The Union of Democratic Mineworkers was founded
- December 12 - Ron Carey died; Michael Ratchford died; Anthony Provenzano died; Charles Ballam died; Tommy Lewis was born
- December 13 - Samuel Gompers died; Bernard Kleiman died; William Spence died; the U.S. Supreme Court decided United States v. Wheeler
- December 15 - George Hardy was born; George W. Taylor died; Chico Mendes was born; Mark Hewitson was born; Clinton Jencks died
- December 16 - The Rothbury riot occurred in 1929 in Australia
- December 17 - Clarence Gillis died; Mustafa al-Hallaj died
- December 18 - The Transport and General Workers' Union and Amicus voted to merge into a new union, Unite, in 2006; the Cincinnati Federation of Teachers was formed; the Supreme Court of Canada issued its landmark ruling in RWDSU v. Dolphin Delivery Ltd.; Douglas Fraser was born; Randi Weingarten was born
- December 19 - Frank Keys Foster was born; the Ford Strike of 1945 in Canada ended; B. T. Ranadive was born
- December 20 - The 2005 New York City transit strike began; two of the Sydney Twelve were executed in Australia in 1916; the Supreme Court of Canada issued its landmark ruling in Dunmore v. Ontario (Attorney General); the Occupational Safety and Health Act became law in the U.S. in 1970; Richard Cordtz was born
- December 21 - William Usery Jr. was born
- December 22 - Chico Mendes died; the 2005 New York City transit strike ended
- December 23 - 1929 Australian timber workers' strike began; Gunnar Sträng was born; Derek Simpson was born; Ella Vogelaar was born
- December 24 - Ed Boyce died; the Electrical Trades Union of Australia was formed; Italian Hall Disaster in 1913
- December 25 - Ed Hochuli was born; Bartholomew Ulufa'alu was born; Philip Vera Cruz was born
- December 26 - A series of general strikes began in 1996 in South Korea; Dave Beck died
- December 27 - Cyrus S. Ching died; Free Workers' Union of Germany was founded; William Konyha died; John La Rose was born; Makhan Singh was born
- December 28 - Agnes Nestor died
- December 29 - Flint sit-down strike began in 1936; the Indian Labour Organization was founded; Ted Theodore was born
- December 30 - Bill Tytla died
- December 31 - The International Typographical Union was dissolved; Joseph Yablonski was murdered on the orders of United Mine Workers president W. A. Boyle; John Garden died