The Knights of Labor was a US labor organization, started in Philadelphia in December 1869 by a group of nine tailors, led by Uriah S. Stephens. Initially a secretive organization, it grew rapidly after 1872 and the collapse of the National Labor Union in 1873. The membership peaked in 1886, under Terence V. Powderly, with a total of over 700,000.
The Knights aided various strikes and boycotts, winning important actions against Union Pacific in 1884 and on the Wabash Railroad in 1885. However, failure in the Missouri Pacific strike in 1886 and violence by strikers, including the Haymarket Square riot, led to disputes between the craft unionists and the advocates of all-inclusive unionism. With the additional problems of an autocratic structure, mismanagement, further unsuccessful strikes, and the emergence of the American Federation of Labor in 1886 under Samuel Gompers the organization quickly shrank from its 1886 peak. By 1890 membership was only 100,000, and in 1900 it was practically non-existent.
With the motto "an injury to one is the concern of all", the Knights of Labor attempted to further its idealistic aims - an 8-hour day, the abolition of child labor, equal pay, the elimination of private banks. The Knights were organized both as all-inclusive "general assemblies" and as "trade assemblies" consisting of workers within particular crafts. Women, black workers (after 1883), and employers were welcomed, and bankers, lawyers, gamblers, and stockholders excluded.
The organization has been associated with Freemasonry, the Ku Klux Klan and strongly racist views.