A teachers’ union is a labor union (an organized group of employees) that represents teachers or educators in contract negotiations (for salaries, tenure, paid time off, and other terms of employment) with schools or school districts. Teachers’ unions are said to engage in collective bargaining—bargaining or negotiating on behalf of all teachers—rather than individual teachers negotiating their own employment terms.

The rights of workers to form unions, strike, bargain collectively, and engage in other work-related activities are provided by the federal statute known as the National Labor Relations Act of 1935 (NLRA). The NLRA also prohibits unions from trying to force workers to join a union and prohibits employers from retaliating against workers who exercise their union rights.

The NLRA supersedes many state laws but it does not apply to employees in the public sector—including public school teachers. Some states have laws that prohibit collective bargaining for public employees (Georgia, North Carolina, South Carolina, Texas, Virginia) and many states have laws that make it illegal for public employees to strike.

In Washington State, teachers' unions operate under state-specific regulations that govern public sector employees, as the National Labor Relations Act (NLRA) does not apply to public school teachers. Washington is not one of the states that prohibit collective bargaining for public employees; instead, it supports collective bargaining rights for public sector employees, including teachers. The Washington Public Employees' Collective Bargaining Act (PECBA) governs the collective bargaining process for public employees in the state. This act allows teachers, through their unions, to negotiate with school districts on various employment terms such as salaries, benefits, working conditions, and other important aspects of their employment. Additionally, while some states may restrict the right to strike for public employees, Washington does not have a blanket prohibition on public sector strikes, although there are legal complexities and potential consequences that can arise from such actions. Teachers' unions in Washington are active and have a history of engaging in collective bargaining and other union activities to advocate for the interests of educators.