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 Minnesota, 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. Minnesota law allows for collective bargaining for public school teachers, which is conducted through teachers' unions. These unions represent the interests of teachers in negotiations with school districts over employment conditions such as salaries, benefits, working conditions, and other terms of employment. The Public Employment Labor Relations Act (PELRA) of Minnesota provides the legal framework for collective bargaining, outlining the rights and obligations of public employers and employees. Under PELRA, teachers have the right to organize and participate in union activities, and it is illegal for employers to retaliate against employees for exercising these rights. Additionally, while Minnesota does not prohibit public employees from striking, there are specific legal processes and requirements that must be followed before a strike can occur. It's important to note that while teachers' unions have significant influence in negotiating contracts, they must operate within the confines of state law.