In Greek mythology, Iphianassa (; Ancient Greek: Ίφιάνασσα, romanized: Īphianassa, lit. 'strong queen' or 'rule strongly') is a name that refers to several characters.
Iphianassa, one of the 50 Nereids, marine-nymph daughters of the 'Old Man of the Sea' Nereus and the Oceanid Doris.
Iphianassa, consort of King Endymion of Elis and mother of Aetolus. The wife of Endymion was otherwise known as Asterodia, Chromia, Hyperippe or a nameless Naiad nymph.
Iphianassa, one of the three Proetids, daughters of the Argive king Proetus by Stheneboea who were purified of their madness by Melampus. Iphianassa eventually married Melampus.
Iphianassa, a Mycenaean princess as the daughter of King Agamemnon and Clytemnestra, perhaps the same as Iphigenia.
Iphianassa, mother of Menalces by Medon of Cilla. Her son was killed by Neoptolemus.