The Fourth Sign, Steel sculpture at University of Hawaii at Manoa, United States.

The Fourth Sign is a steel sculpture on the lawn outside the Art Building at the University of Hawaiʻi at Mānoa. Nine straight sections are fused end to end into a broken circle: three horizontal sections rest on the ground, and two broad arches of three sections each connect them, leaving a break at the 6 o'clock position. The work is painted black.

The sculpture was commissioned in 1976 and fabricated by Hawaii Welding Company under Mamoru Sato's supervision. Support from the National Endowment for the Arts helped bring this public artwork to the campus and establish it as a lasting part of the university landscape.

The title refers to Cancer, the fourth zodiac sign, and many viewers read the angled uprights and sloping sections as a crab's legs and claws. In 1978 the Honolulu artist and professor of religion John Charlot wrote that students draped themselves over the steel and nestled inside its circle, treating it as part of campus life.

The sculpture sits in an open outdoor space on campus and is easy to find near the Art Building. Since it is fully exposed to the elements, it looks different depending on the time of day and weather conditions.

The edition is limited to this single piece, completed in 1977 at a cost of $65,000, with a $20,000 grant from the National Endowment for the Arts. Smith had proposed two other campus projects, Haole Crater and Hubris, but only The Fourth Sign was realized. In 1998 it was noted that virtually all of the campus's outdoor pieces were in stages of disrepair.