The International Union of Operating Engineers (IUOE) is a progressive, diversified trade union that primarily represents operating engineers, who work as heavy equipment operators, mechanics, and surveyors in the construction industry, and stationary engineers, who work in operations and maintenance in building and industrial complexes, and in the service industries.

Founded in 1896, IUOE today has approximately 400,000 members in 123 local unions throughout the United States and Canada. IUOE is the 10th largest union in the AFL-CIO. Over 100 state-of-the-art training and apprenticeship programs ensure that IUOE members are the safest, most productive, and highly skilled craft workers.