Uriah Smith Stephens (August 3, 1821 – February 13, 1882) was an American labor leader. He was most notable for his leadership of nine Philadelphia garment workers in founding the Knights of Labor in 1869, a successful early American labor union.

Born in New Jersey, and initially educated for the ministry, Stephens was apprenticed as a tailor when he was a teenager so that he could help support his family. He settled in Philadelphia, where he continued to work at his trade. After extensive travel throughout the western United States, Mexico, and Europe in the late 1840s and early 1850s, he returned to Philadelphia, where he worked as a tailor and became active in fraternal organizations and the labor movement. After an initial effort, the Garment Cutters' Union, failed to take root, in 1869 Stephens founded the Knights of Labor. He originally conceived of the organization as a fraternal one that included secret rituals and focused on individual personal and professional development. As the organization expanded, debates over the need for secrecy and rituals eventually ended when Stephens resigned, and the organization voted to eliminate these requirements, which enabled it to then begin recruiting as members workers and tradesmen who were Catholic.

Stephens remained active in the labor movement after leaving the Knights of Labor, and died in Philadelphia in 1882. The Knights of Labor continued to expand until backlash against unions following the Haymarket affair and the Panic of 1893 caused workers to depart the K of L, and its membership declined until the organization became defunct in 1949. Stephens' primary legacy was as the founder and organizer of one of the first successful nationwide labor unions.