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 Iowa, teachers' unions operate under state-specific regulations, as the National Labor Relations Act (NLRA) does not apply to public sector employees, including public school teachers. Iowa allows collective bargaining for public employees, including teachers, but with certain limitations. The Iowa Public Employment Relations Act (PERA) governs collective bargaining for public employees in the state. Under PERA, teachers can negotiate on a limited set of issues, including wages, insurance, and other employment benefits. However, as of recent changes to the law, they are restricted from bargaining over broader issues such as evaluation procedures, staff reduction, and leave of absence details. Iowa law also prohibits public employees from striking. Teachers' unions in Iowa, therefore, can engage in collective bargaining within the scope allowed by state law, but they do not have the same range of bargaining rights as private-sector unions under the NLRA, and they must adhere to the restrictions on striking and the subjects of bargaining as outlined by state statutes.