Pomacanthus imperator, known as the emperor angelfish, belongs to the family Pomacanthidae, which inhabits tropical and subtropical waters worldwide. P. imperator occurs in many localities of the Indian and Pacific oceans. In the Mediterranean Sea, P. imperator was reported from its southern Levantine Sea for the first time in 2010. Subsequently, it has been reported again from the same area, and from the Syrian, Turkish, and Egyptian waters. However, until today, only the non-indigenous lessepsian Pomacanthus maculosus was reported from the Lebanese waters. Therefore, this note constitutes the first record of the non-indigenous P. imperator in Lebanese waters.