Barbara Mayer Wertheimer (1926-September 23, 1983) was an American labor historian and labor organizer from the 1940s through the early 1980s.

From 1947 to 1948 Ms. Wertheimer was an organizer and acting education director for the Amalgamated Clothing Workers of America. She worked briefly for the American Labor Education Service and then from 1961 to 1966 as a consultant for the New York State Division of Housing and Community Renewal. In 1966 Ms. Wertheimer joined the New York State School of Industrial and Labor Relations at Cornell University. While at Cornell she was a senior extension associate, director of the Trade Union Women’s Studies program, and, from 1977 on, an associate professor and director of the Institute for Women and Work, which she cofounded. Ms. Wertheimer remained at Cornell until her death in 1983.

Ms. Wertheimer is well known for her monograph “We Were There: The Story of Working Women in America” (1977).