National Labor Relations Board v Jones & Laughlin Steel Corporation, 301 U.S. 1 (1937), was a United States Supreme Court case that upheld the constitutionality of the National Labor Relations Act of 1935, also known as the Wagner Act. The case represented a major expansion in the Court's interpretation of Congress's power under the Commerce Clause and effectively spelled the end to the Court's striking down of New Deal economic legislation.

The Jones and Laughlin Steel Corporation, also known as J&L Steel or simply as J&L, was an American steel and iron manufacturer that operated from 1852 until 1968. Beginning as the American Iron Company, founded in 1852 by Bernard Lauth and Benjamin Franklin Jones, a few miles south of Pittsburgh along the Monongahela River. Lauth's interest was bought in 1854 by James Laughlin. The first firm to bear the name of Jones and Laughlin was organized in 1861, and headquartered at Third & Ross in downtown Pittsburgh.