Sigma Tau (ΣΤ) was an American honor society in the field of engineering.

It was founded at the University of Nebraska in 1904 and merged with Tau Beta Pi in 1974.

Sigma Tau was founded at the University of Nebraska on February 24, 1904 by fourteen faculty members and students in the College of Engineering.

Membership was chosen from the upper one-third of the junior and senior classes at recognized engineering schools.

Selection from those men and women is made on the further basis of practicality and sociability.