157 Dejanira is a main belt asteroid that was discovered by Alphonse Borrelly on 1 December 1875, and named after the warlike princess Deianira in Greek mythology (Δηιάνειρα in Greek).

The Dejanira family of asteroids is named after it.

Photometric observations of this asteroid were made in early 2009 at the Organ Mesa Observatory in Las Cruces, New Mexico.

The resulting light curve shows a synodic rotation period of 15.825 ± 0.001 hours.

This article about an asteroid native to the asteroid belt is a stub.