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 Oklahoma, teachers' unions operate within the context of state statutes that govern public sector labor relations, as the National Labor Relations Act (NLRA) does not apply to public school teachers. Oklahoma does not prohibit collective bargaining for public employees, including teachers. Instead, the state has provisions that allow for collective bargaining in the public sector. The Oklahoma Public Employees Labor Relations Act provides a legal framework for union activities, including collective bargaining. However, it's important to note that while collective bargaining is permitted, there are restrictions on the right to strike for public employees in Oklahoma. Strikes by public employees are generally considered illegal, and participating in a strike can lead to consequences such as fines or termination of employment. Therefore, while teachers' unions can negotiate contracts and represent teachers in various employment matters, they must do so within the constraints of state law, which includes the prohibition of strikes.