The Equal Pay Act was an effort to correct a centuries-old problem of gender-based wage discrimination.

Women made up a quarter of the American workforce by the early 20th century, but they were traditionally paid far less than men, even in cases where they performed the same job. In some states, female workers were also forced to contend with laws that restricted their working hours or prohibited them from working at night.

Efforts to correct the wage gap escalated during World War II, when scores of American women entered factory jobs in place of men who had enlisted in the military. In 1942, for example, the National War Labor Board endorsed policies to provide equal pay in instances where women were directly replacing male workers.

Three years later in 1945, the U.S. Congress introduced the Women’s Equal Pay Act, which would have made it illegal to pay women less than men for work of “comparable quality and quantity.” The measure failed to pass, however, and despite campaigns by women’s groups, little progress was made on pay equity during the 1950s.

By 1960, women still earned less than two-thirds of what their male counterparts were paid.

Calls for a federal equal pay law coalesced in the early 1960s during the administration of President John F. Kennedy.

Esther Peterson, head of the Women’s Bureau of the Department of Labor, was a vocal supporter of the proposed legislation, as was former First Lady Eleanor Roosevelt, who chaired Kennedy’s Presidential Commission on the Status of Women. Representatives Katharine St. George and Edith Green helped lead the charge for a bill in Congress.

Despite the opposition of powerful business groups such as the Chamber of Commerce and the Retail Merchants Association, Congress passed the Equal Pay Act in 1963 as an amendment to the Fair Labor Standards Act of 1938.

In its final form, the Equal Pay Act mandates that employers cannot award unequal wages or benefits to men and women working jobs that require “equal skill, effort, and responsibility, and which are performed under similar working conditions.”

The law also includes guidelines for when unequal pay is permitted, specifically on the basis of merit, seniority, workers’ quality or quantity of production and other factors not determined by gender.

The Equal Pay Act was among the first federal laws in American history to address gender discrimination. In signing it into law on June 10, 1963, Kennedy praised it as a “significant step forward,” but acknowledged that “much remains to be done to achieve full equality of economic opportunity” for women.

Among other things, Kennedy stressed the need for child day care centers to support working mothers.

Following the passage of the Equal Pay Act, several other laws were enacted with the aim of reducing employment discrimination.

Perhaps the most important was Title VII of the Civil Rights Act of 1964, which banned employers from discriminating on the basis of “race, color, religion, sex, or national origin.”

The Educational Amendment of 1972, meanwhile, expanded the reach of the Equal Pay Act to include white-collar executive, professional and administrative jobs—categories that had been exempted under the original law.

Other important gender equity employment laws include the Pregnancy Discrimination Act of 1978, which strengthened protections for pregnant workers; and 2009’s Lilly Ledbetter Fair Pay Act, which reduced time restrictions on wage discrimination complaints.

Under the regulations of the Equal Pay Act, employees who believe they are being discriminated against can either file a complaint with the Equal Employment Opportunity Commission or directly sue their employer in court. Combined with increased education and career opportunities for women, these regulations have been credited with helping to narrow the gender wage gap in the United States.

Nevertheless, studies show that women are still paid less than men on average. Estimates vary, but according to a study from the Bureau of Labor Statistics, full-time women workers in 2016 were paid 82 cents for every dollar men earned.

The Equal Pay Act of 1963. U.S. Equal Opportunity Employment Commission.
Facts About Equal Pay and Compensation Discrimination. U.S. Equal Opportunity Employment Commission.
Work in America: An Encyclopedia of History, Policy, and Society, Volume One. Edited by Carl E. Van Horn and Herbert A. Schaffner.
Equal Pay Act of 1963. National Park Service.
Inch by Inch: Gender Equity Since the Civil Rights Act of 1964. By Mary E. Guy and Vanessa M. Fenley.
The History of the Battle for Equal Pay for American Women. Time Magazine.