Drug delivery to the inner part of the eye is still a problem in treatment of ocular disease. Iontophoresis has been used in the field of medicine for many years. This technique consists of applying a weak electrical current to drive charged drug molecules across tissue barriers. Transcorneal iontophoresis delivers a high concentration of drug to the anterior segment of the eye (cornea, aqueous humor, ciliary body, iris, and lens), for the treatment of anterior segment diseases. There are different types of iontophoresis such as ophthalmic, transdermal, transungual, oral, buccal, and transnasal. The benefit of iontophoretic drug delivery in ophthalmology lays in its capacity to provide high drug tissue concentration safely, while minimizing the systemic drug exposure. This review summarizes basics of ocular iontophoresis and iontophoretic device, trans corneal and transscleral iontophoresis, and the applications of iontophoresis in ophthalmology.