An unfair labor practice is a violation of specific provisions of the laws administered by the National Labor Relations Board (NLRB), and state laws, which vary by state, that may be committed by either the employer or the union. Unfair labor practices by management were largely outlawed by the National Labor Relations Act. Unfair labor practices by labor unions were largely outlawed by the Taft-Hartley Act.
For example, it is illegal for management to threaten or retaliate against employees for seeking union representation or to refuse to provide a union information that the law requires the agency to provide. Similarly, unions may not try to influence management to discipline employees who did not join the union or refuse to represent employees because they are not union members. Neither an agency nor a union may refuse to bargain with the other in good faith.