Retaliation includes any adverse action taken against an employee for filing a complaint, supporting another employee’s complaint, or engagin in other protected actvity under a variety of laws. The most common type of retaliation claim involves an employee who alleges that she was first harassed or discriminated against and later punished for making a complaint to her employer or a relevant federal agency.

Employers also are prohibited from punishing employees for exercising other rights assured to them. For example, employers can't retaliate against an employee who asks for a reasonable accommodation of her disability under the Americans with Disabilities Act or who applies for medical leave under the Family and Medical Leave Act. Employers also must be careful not to retaliate against employees who file Title VII of the Civil Rights Act of 1964 (Title VII) complaints of harassment or discrimination.

It’s also illegal to retaliate against an employee for opposing an illegal employment practice, or for testifying, assisting, or participating in any manner in an investigation, proceeding, or hearing under some statutes. For example, employers must be wary of violating the Uniformed Services Employment and Reemployment Rights Act (USERRA) by retaliating against such employees. This applies even to individuals who haven't served in the military.

The Sarbanes-Oxley Act is another avenue an employee can take in pursuing a retaliation claim against an employer. The Act’s “whistleblower” provision prohibits publicly traded companies and their officers, employees, contractors, subcontractors, and agents from retaliating against employees who blow the whistle by either reporting a violation of securities and fraud laws to the proper authorities or by assisting in an existing investigation that’s related to a violation of federal securities or fraud laws.

Part of what makes retaliation claims so dangerous is that there are an infinite number of ways for an unwitting employer to do something that looks like retaliation even though it isn’t intended to be. In fact, to prevail on a retaliation claim, there’s no requirement that whatever the employee complained about in the first place was actually illegal.

All that’s required is that the employee reasonably believed she was complaining about something that was illegal. It's also possible for an employee's discrimination or harassment claim not to have enough merit to hold up in court, but if her employer took adverse action against her after she complained or filed the claim, she might have a legitimate retaliation claim.

For that very reason, it’s not unusual for an employee’s retaliation claim to survive even after her underlying claim of discrimination or harassment is dismissed.