Significant dates in labour history.

• September 01 - Walter Reuther was born; William Z. Foster died; International Brotherhood of Boilermakers was formed; Working America was founded
• September 02 - Federal troops intervened in the Battle of Blair Mountain in 1921 in the U.S.; Franz Leopold Neumann died; the Rock Springs massacre occurred in 1885 in the U.S.
• September 04 - The Textile workers strike of 1934 began in the U.S.; former unionist Francisco Largo Caballero became prime minister of Spain; Thomas R. Donahue was born
• September 05 - Victor Gotbaum was born; Elizabeth Gurley Flynn died
• September 06 - Johan Nygaardsvold was born
• September 07 - Southampton Dock strike of 1890 began in the U.K.; Ela Bhatt was born; Cornelius Shea was born
• September 08 - The Delano grape strike began in 1965 in the U.S.; Kenneth Yablonski died; Ben Gold was born
• September 09 - John Mitchell died; the Hanapepe massacre occurred in 1924 in the Hawaii
• September 10 - Lattimer massacre occurred in the U.S.
• September 11 - Russell Crowell died
• September 12 - Tom Mooney was born; George L. Berry was born
• September 13 - Amado V. Hernández was born; Carlos Bulosan died; George Hardy died
• September 14 - Albert Shanker was born; the Labor Management Reporting and Disclosure Act became law in the U.S.; the U.S. Steel recognition strike of 1901 ended in the U.S.; Leon J. Davis died; the German Trade Union of the Police was founded in 1950; James Duncan died
• September 15 - The Invergordon Mutiny occurred in 1931 in the U.K.; the Free Workers' Union of Germany was founded in 1919
• September 16 - The 2004–05 NHL lockout began in the U.S. and Canada; the Farm Labor Organizing Committee signed a first contract with the Mt. Olive Pickle Company in the U.S.
• September 17 - Miguel Contreras was born; David Dubinsky died; the National Federation of Federal Employees was formed
• September 18 - Sandra Feldman died; James Scullin was born; Teamsters for a Democratic Union was founded; Thomas E. Scanlon was born; Mary Lee died
• September 19 - Joe Glazer died; the National Football League Players Association struck in 1982 in the U.S.
• September 20 - Lewis B. Schwellenbach was born; Sam Church was born; Nathan Feinsinger was born; the Namibia Food and Allied Workers Union was founded
• September 21 - John White died; Arlene Holt Baker became the first African-American officer of the AFL–CIO in 2007
• September 22 - Steel strike of 1919 began in the U.S.; the Winter of Discontent began in the U.K. as workers struck Ford
• September 23 - The Sydney Twelve were arrested in 1916 in Australia
• September 24 - The Workers Trade Union Law is passed in Bahrain
• September 25 - The Atomic Trades and Labor Council was founded; the Health Professionals and Allied Employees conducted its first strike in 1979 in the U.S.
• September 26 - The Temple University Graduate Students Association was founded
• September 27 - The Santa Barbara News-Press unionization effort began in the U.S.; the Change to Win Federation was formed
• September 28 - Alice Mahon was born
• September 29 - The Liverpool dockers' strike began in 1995 in the UK.
• September 30 - Ignatius Wolfington died; the first legal version of Solidarity was formed in 1985 in Poland