What is "yellow-dog contract"

n. a now-illegal labor contract whereby the employee agrees not to join a trade union

A yellow-dog contract (a yellow-dog clause of a contract, or an ironclad oath) is an agreement between an employer and an employee in which the employee agrees, as a condition of employment, not to be a member of a labor union. In the United States, such contracts were, until the 1930s, widely used by employers to prevent the formation of unions, most often by permitting employers to take legal action against union organizers. In 1932, yellow-dog contracts were outlawed in the United States under the Norris-LaGuardia Act.

The term yellow-dog clause can also have a different meaning: non-compete clauses within or appended to a non-disclosure agreement to prevent an employee from working for other employers in the same industry.