Ibiranu (reigned c. 1235 BC – c. 1225/20 BC) was the sixth king of Ugarit, a city-state in northwestern Syria. He was the second-eldest son of Ammittamru II. Ibiranu's older step-brother and heir apparent to the throne, Utri-Sarruma, decided to leave the kingdom when his mother's marriage was annulled, and Ibiranu became the next king of Ugarit. Ibiranu reigned between c. 1235 and 1225/20 BC, and was a contemporary of Tudhaliya IV and Arnuwanda III of Hatti. As a vassal state of Hatti the king was answerable to the viceroy at Carchemish. After he became king, Ibiranu failed to present himself to the Hatti overlord as the diplomatic protocol of a vassal state required him to do. His failure to do so, and to send valuable gifts to compensate for his mistake raised concerns and he received several letters of reprimand from the local viceroy, Ini-Teshup, and the king's son, Pihawalwi. The letters, discovered among the cuneiform tablets found at Ugarit, also revealed that Ibiranu failed to send sufficient troops to participate in the king's campaigns. On suspicion that Ibiranu was keeping his best chariots in Ugarit, a letter from the Carchemish viceroy states that an inspector from the Hatti king would be sent to Ugarit to verify the number of troops at Ibiranu's disposal. The king's reluctance to present his allegiance to the Hittites seems to suggest a loss of confidence in their protection. This explanation is corroborated by a letter found in the Ugaritic archives addressed to Ibiranu from the Assyrian king, Tukulti-Ninurta I, describing the heavy defeat he inflicted on the Hittites in northern Mesopotamia.