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 Maine, teachers' unions operate under state-specific statutes that govern public sector employees, as the National Labor Relations Act (NLRA) does not apply to public school teachers. Maine allows public sector employees, including teachers, to engage in collective bargaining through their unions. The Maine Labor Relations Board administers the collective bargaining laws for public employees. These laws provide a framework for union representation, contract negotiations, and dispute resolution. Maine does not prohibit collective bargaining for public employees, and unlike some states, it does not make it illegal for public employees to strike. However, there are specific regulations and procedures that must be followed for a strike to be lawful. Teachers' unions in Maine play a significant role in negotiating terms of employment such as salaries, benefits, and working conditions on behalf of their members.