In most cases, no. Firing an employee for discussing their salary with coworkers, for trying to form or join a union, or for joining a lawful strike is generally illegal under federal law. These activities are protected by the National Labor Relations Act (NLRA), and terminating someone because of them is what labor lawyers call a "per se" violation, meaning the firing itself is unlawful regardless of how at-will the employment otherwise is. The agency that enforces this is the National Labor Relations Board (NLRB), an independent federal agency.
This is one of the biggest surprises for both workers and managers. "At-will employment" means an employer can usually fire someone for any reason or no reason at all, but it does not mean they can fire someone for an illegal reason. Protected concerted activity under the NLRA is one of the most important exceptions to at-will employment, and it applies to far more workplaces than most people assume.
The Federal Baseline: Section 7 of the NLRA
The core protection comes from Section 7 of the National Labor Relations Act. It gives employees the right to engage in "concerted activities for the purpose of collective bargaining or other mutual aid or protection." Section 8 then makes it an "unfair labor practice" for an employer to interfere with, restrain, coerce, or retaliate against employees for exercising those rights.
The word that does the heavy lifting is concerted. Activity is protected when it is done with or on behalf of other employees, not solely for one person's own benefit. Two or more employees talking about wages is concerted. One employee raising a group concern, or trying to get coworkers to act together, is usually concerted. One employee griping only about their own personal situation, with no connection to group action, may not be.
A crucial point that catches many employers off guard: you do not need a union for the NLRA to apply. These rights protect most private-sector employees whether or not a union exists or is even being discussed. The law covers most private employers engaged in interstate commerce, which the NLRB interprets broadly.
Discussing Salary and Pay
Employees have a protected right to discuss their wages, benefits, and working conditions with each other. This is classic concerted activity, because pay talk is how workers identify whether they are being treated fairly and decide whether to act together.
Workplace "pay secrecy" rules, the kind that tell employees they may not discuss their salaries, are generally unlawful under the NLRA, and firing or disciplining someone for breaking such a rule is itself a violation. Many states have layered additional pay-transparency protections on top of the federal floor, and these vary by state, with some requiring employers to post salary ranges or barring questions about salary history. The federal NLRA protection, however, exists almost everywhere in the private sector.
One nuance: employees whose actual job is to handle confidential payroll or HR data may be restricted in what they can disclose in that capacity. But that narrow exception does not let an employer ban ordinary workers from comparing their own paychecks.
Pay Discrimination Overlaps Here Too
If pay differences break down along lines of sex, race, age, or another protected trait, separate laws come into play: the Equal Pay Act and Title VII of the Civil Rights Act of 1964 (enforced by the Equal Employment Opportunity Commission, the EEOC), the Age Discrimination in Employment Act (ADEA), and state equal-pay statutes. Workers often can't spot illegal pay discrimination at all without first being free to discuss pay, which is exactly why the NLRA protection matters.
Unionizing and Organizing
Trying to form, join, or assist a union is squarely protected. So is talking to coworkers about unionizing, distributing union literature in non-work areas during non-work time, wearing union insignia in many settings, and signing or circulating authorization cards. An employer may not fire, demote, threaten, interrogate, surveil, or promise benefits to discourage these activities.
Employers are allowed to express their own views about unionization, but they cross the line into an unfair labor practice when they threaten ("we'll close if you organize"), interrogate employees about union sympathies, promise benefits to buy votes, or spy on organizing. Labor lawyers summarize the forbidden conduct with the acronym TIPS: Threats, Interrogation, Promises, Surveillance.
If a worker is fired during an organizing campaign, the timing alone can be powerful evidence. The NLRB looks at whether the employer knew about the activity, whether there was anti-union animus, and whether the stated reason for firing is a pretext.
Going on Strike
The right to strike is also protected by Section 7, but the protection depends on the type and conduct of the strike. Lawful economic strikes and unfair-labor-practice strikes are protected activity, and firing someone simply for participating is illegal. However, the rules around striker reinstatement differ: unfair-labor-practice strikers generally must be reinstated, while economic strikers can sometimes be permanently replaced (a legal distinction from being "fired") though they retain certain recall rights.
Some strikes lose protection. These can include strikes that violate a no-strike clause in a current collective bargaining agreement, "intermittent" or repeated partial walkouts designed to harass, sit-down strikes where employees occupy the premises, and strikes involving serious misconduct or violence. Because these lines are technical, this is an area where talking to a labor lawyer early really matters.
What About "Talking Bad" About the Company?
This is where it gets nuanced. Employees often have a protected right to criticize their employer, including publicly or on social media, when the criticism relates to wages, hours, working conditions, or other terms of employment and is connected to group concerns. A social-media post complaining about understaffing, unpaid overtime, or unsafe conditions, especially one that involves or invites coworkers, can be protected concerted activity. Overly broad social-media or "loyalty" policies that chill these discussions have repeatedly been struck down.