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 South Carolina (SC), public school teachers are not permitted to engage in collective bargaining through teachers' unions. While the National Labor Relations Act of 1935 (NLRA) provides private sector employees with the right to form unions, strike, and bargain collectively, it does not extend these rights to public sector employees, including public school teachers. South Carolina is one of the states that explicitly prohibits collective bargaining for public employees. Additionally, it is illegal for public employees in South Carolina to go on strike. Therefore, in SC, teachers' unions may exist for advocacy and support purposes, but they do not have the legal authority to negotiate contracts or engage in collective bargaining on behalf of teachers with school districts.