Keratoconus (KC) is the most common corneal ectatic disorder characterized by asymmetric cone-shaped corneal protrusion. The pathophysiology of KC is still unclear. For many years, KC has been considered as a noninflammatory degenerative disease. However, several studies suggested that inflammatory mediators play a role in KC pathogenesis. Tear film contains various mediators that reflect ocular surface diseases. Monitoring the changes in tear composition can be used as a diagnostic tool. In this review, the adequacy of tear markers in the diagnosis of KC was discussed.