Frank J. Weber (August 7, 1849 – February 4, 1943) was a seaman, carpenter and union organizer from Milwaukee who between 1907 and 1926 served five (non-continuous) terms as a Socialist member of the Wisconsin State Assembly.

After completing apprenticeship, Weber became an able seaman and sailed on Great Lakes and Atlantic Ocean merchant ships (according to his 1906 official biography, "in which capacity he visited all the most important seaports of the world").

In 1887 he helped organize the Milwaukee Federated Trades Council, becoming its secretary in 1902: an office he would hold until his retirement in January 1934.

Weber fought to align the State Federation of Labor with the goals and principles of the Social Democratic Party (as it was long known in Wisconsin).

[4] In the Assembly Weber worked for the passage of laws establishing the Wisconsin Industrial Commission (with Charles H. Crownhart and John R. Commons he wrote the industrial commission law in 1911), workmen's compensation, the state system of technical education, and other statutes favorable to the interests of the working class.