Endothelin is a potent vasoactive peptide occurring in three isotypes (ET-1, ET-2 and ET-3). Endothelin via its two main receptors ETA and ETB is responsible for a variety of physiological functions primarily blood flow control. Recent evidence from both human and experimental optic neuropathies shows involvement of endothelin and upregulation of its receptors (principally ETB). Experimental studies have shown that chronic ET-1 administration to the optic nerve immediately behind the globe causes neuronal damage, activation of astrocytes, the major glial cell in the anterior optic nerve and upregulation of ETB receptor. This review outlines the ubiquitous role of endothelin and its potential involvement in glaucoma.