Discrimination law in the United States: an employer's guide
Reviewed by Mellow Editorial Team, HR & payroll content team
Discrimination law in the United States is a layered framework of federal, state, and local rules that prohibit employers from treating workers or job applicants less favorably because of protected characteristics. Getting it wrong carries real financial and reputational risk, so understanding the basics is essential for any employer.
The federal foundation
Several federal statutes form the baseline that applies to most US employers:
Title VII of the Civil Rights Act (1964) prohibits discrimination based on race, color, religion, sex, and national origin. It covers employers with 15 or more employees and is enforced by the Equal Employment Opportunity Commission (EEOC).
The Age Discrimination in Employment Act (ADEA) protects workers aged 40 and over from discrimination based on age. It also applies to employers with 20 or more employees.
The Americans with Disabilities Act (ADA) prohibits discrimination against qualified individuals with disabilities and requires employers to provide reasonable accommodation unless doing so would cause undue hardship. The 15-employee threshold applies here too.
The Equal Pay Act (EPA) requires that men and women receive equal pay for substantially equal work performed under similar conditions at the same establishment.
The Pregnancy Discrimination Act treats discrimination based on pregnancy, childbirth, or related medical conditions as a form of sex discrimination under Title VII.
More recently, the Pregnant Workers Fairness Act (PWFA), which took effect in 2023, requires covered employers to provide reasonable accommodations for known limitations related to pregnancy or childbirth — even when a worker is not disabled under the ADA.
One critical point: these federal laws set a floor, not a ceiling.
State and local law adds more layers
States, counties, and cities frequently extend protections beyond the federal baseline. Common additions include:
- Lower employee thresholds. Some states apply anti-discrimination rules to employers with as few as one employee.
- Broader protected classes. Many jurisdictions protect sexual orientation, gender identity, marital status, source of income, or military status explicitly — even where federal law is silent or ambiguous.
- Stronger remedies. State law often allows larger damages or longer windows to file a complaint than federal law does.
California, New York, and Illinois are among the states with the most expansive employment discrimination frameworks. If you operate across multiple states, you need to account for each jurisdiction's specific rules. As a reminder, California also prohibits most non-compete clauses, which illustrates how significantly state law can diverge from what might be customary elsewhere.
What discrimination actually looks like in practice
Discrimination does not have to be intentional to be unlawful. US law recognizes two main theories of liability:
Disparate treatment is intentional discrimination — for example, refusing to promote an employee because of their religion, or asking only female candidates about childcare arrangements during interviews.
Disparate impact occurs when a facially neutral policy disproportionately harms a protected group and is not justified by business necessity. A hiring test that screens out applicants of a particular race at a higher rate, even unintentionally, can be challenged on this basis.
Harassment is also a form of discrimination. Under Title VII, severe or pervasive conduct based on a protected characteristic that creates a hostile work environment is unlawful. This includes conduct by supervisors, coworkers, and in some circumstances, third parties like contractors or clients.
Reasonable accommodation: a practical obligation
Both the ADA and the PWFA require employers to engage in an interactive process with an employee who requests accommodation. This means having a good-faith dialogue to identify what limitation the employee has, what they need, and what options the employer can feasibly offer.
Accommodation does not mean automatic approval of whatever an employee requests. An employer can decline an accommodation that would impose an undue hardship — meaning significant difficulty or expense relative to the size and resources of the business. However, the bar for claiming undue hardship is high, and employers who refuse accommodation without properly engaging the interactive process take on substantial legal exposure.
Building compliant HR practices
Compliance is easier to maintain when it is built into routine processes rather than addressed reactively. Practical steps include:
Job postings and interviews. Base hiring criteria on genuine job requirements. Avoid questions about age, disability status, national origin, family plans, or religion. Document the legitimate, job-related reasons behind every hiring decision.
Policies and training. A written anti-harassment and anti-discrimination policy, distributed to all employees, is a baseline expectation. Regular manager training matters too — supervisors are often the first point of contact for complaints, and how they respond can determine whether a problem escalates.
Complaint handling. Have a clear internal reporting procedure. When a complaint comes in, investigate promptly and impartially, document your process, and take appropriate corrective action. Retaliation against an employee for raising a discrimination concern is itself unlawful under every major anti-discrimination statute.
Record-keeping. The EEOC recommends retaining personnel records for at least one year from the date of the employment decision. Some state laws require longer retention periods.
This article is general information only and does not constitute legal advice. Employment discrimination law is fact-specific and jurisdiction-dependent. Consult qualified employment counsel for guidance on your particular situation.
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