Are some kinds of employees not covered by Social Security?

Yes. According to the Congressional Research Service, 94 percent of U.S. workers are "covered," meaning they pay into the Social Security system via payroll or self-employment taxes. But there are groups of “non-covered” employees. These include:

• Some state, county and municipal employees whose agencies do not participate in Social Security but provide state-funded pensions.
• Employees of the U.S. government who were hired before 1984, the year federal agencies came under the Social Security umbrella. These longtime federal employees get pensions under the old Civil Service Retirement System. 
• Railroad employees, who are covered by a separate pension system that came into being in the 1930s, around the same time as Social Security.
• Foreign nationals who work in the United States for their home governments or for some international organizations, such as the United Nations. (U.S. citizens who work in the United States for foreign governments — say, an American employed by the French Embassy in Washington — do pay Social Security taxes and are covered.)

Contrary to a persistent urban legend, members of Congress are covered by Social Security. Like other U.S. government employees, they’ve paid into the system since 1984. 

No more reduction for pension

While the jobs listed above are not covered by Social Security, the people who fill them may have accumulated enough earnings in part-time or second-career jobs in the private sector to qualify for both a non-covered pension and Social Security retirement benefits.

Such workers used to be subject to a Social Security rule called the Windfall Elimination Provision (WEP) that could reduce benefits for retirees who collected a non-covered pension. Congress repealed the WEP in December 2024 and there is no longer any benefit impact from receiving a non-covered government pension.