Sex discrimination involves treating someone (a job applicant or employee) unfavorably because of that person's sex. Sex discrimination is a form of employment discrimination that violates federal law—including Title VII of the Civil Rights Act of 1964 (42 U.S.C. §2000e).

In addition to these federal laws, states also have laws against sex discrimination in employment. These state laws are generally located in a state’s statutes—often in the labor code or employment-related statutes.

Discrimination against an individual because of gender identity—including transgender status or sexual orientation—is discrimination because of sex in violation of Title VII.

The law forbids discrimination when it comes to any aspect of employment, including hiring, firing, pay, job assignments, promotions, layoff, training, fringe benefits, and any other term or condition of employment.

For the regulations related to sex discrimination, see the Code of Federal Regulations, beginning with 29 CFR 1604.1.

In California, sex discrimination in employment is prohibited under both federal and state law. Federally, Title VII of the Civil Rights Act of 1964 makes it illegal to discriminate based on sex in any aspect of employment. This includes hiring, firing, pay, job assignments, promotions, layoffs, training, benefits, and other terms or conditions of employment. Additionally, Title VII has been interpreted to include discrimination based on gender identity and sexual orientation. For the specific regulations, one can refer to the Code of Federal Regulations starting at 29 CFR 1604.1. At the state level, the California Fair Employment and Housing Act (FEHA) also prohibits sex discrimination, as well as discrimination based on gender identity, gender expression, and sexual orientation. FEHA applies to public and private employers, labor organizations, and employment agencies and is more expansive than federal law, offering protections to a larger group of individuals and in some cases, to employers with fewer employees than federal law covers. California's Department of Fair Employment and Housing (DFEH) is the state agency charged with enforcing these laws and handling complaints of discrimination.