The Tau Beta Pi Association (commonly Tau Beta Pi, ΤΒΠ, or TBP) is the oldest engineering honor society in the United States and the second oldest collegiate honor society in America. It honors engineering students who have shown a history of academic achievement as well as a commitment to personal and professional integrity. Specifically, the association was founded "to mark in a fitting manner those who have conferred honor upon their Alma Mater by distinguished scholarship and exemplary character as students in engineering, or by their attainments as alumni in the field of engineering, and to foster a spirit of liberal culture in engineering colleges."
When academic honor society Phi Beta Kappa sought to restrict its membership to students of the liberal arts in the late 19th century, Edward H. Williams Jr., a member of Phi Beta Kappa and head of the mining department at Lehigh University, formulated the idea of an honor society for those studying technical subjects. Irving Andrew Heikes, the valedictorian of his class at Lehigh, was initiated as the first student member of Tau Beta Pi on June 15, 1885. A statue on Lehigh's campus commemorates this event. In 1892, a second chapter was established at Michigan State University. Since then, the association has grown to 234 student chapters across the United States and Puerto Rico. Tau Beta Pi was a founding member of the Association of College Honor Societies. The national headquarters of Tau Beta Pi are currently located in Knoxville, Tennessee on the campus of the University of Tennessee. Although Tau Beta Pi never discriminated on the basis of race or religion, Tau Beta Pi did make its start as a male-only society. Female engineering students were scholastically eligible for Tau Beta Pi as early as 1902; however, those women were not granted membership. Starting in 1936, TBP awarded a women's badge to exceptional female engineering students, and a total of 619 women's badges were awarded until 1969. In 1969, Tau Beta Pi began granting women full membership in the society. In 1974, the Sigma Tau fraternity merged with Tau Beta Pi. Sigma Tau was an honor society for engineering much like Tau Beta Pi and was founded at the University of Nebraska in 1904. At the time of the merger, Sigma Tau consisted of 34 collegiate chapters and a total membership of 45,000. The basis of the merger of Tau Beta Pi and Sigma Tau was the conviction that a single, strong honor society would better serve the engineering profession. The colors of Tau Beta Pi are seal brown and white, which are the school colors of Lehigh. The official badge, called the Bent, is a watch key in the shape of the bent of a trestle (see picture). The trestle is the load-bearing part of the bridge, representing Tau Beta Pi's principle of Integrity and Excellence In Engineering. Originally the keys could be used to wind watches, but modern keys do not. The quarterly magazine of Tau Beta Pi is also titled The Bent.