Gertus or Gertous (Greek, Ancient (to 1453);: Γερτοῦς<ref name=Polybius>[[Polybius]]. ''The Histories'', 5.108.2: "ῆς δὲ Δασσαρήτιδος προσηγμένον πόλεις, τὰς μὲν φόβῳ, τὰς δ’ ἐπαγγελίαις, Ἀντιπάτρειαν, Χρυσονδύωνα, Γερτοῦντα, πολλὴν δὲ καὶ τῆς συνορούσης τούτοις Μακεδονίας"</ref>) was an ancient town in the southern Illyrian region of Dassaretia, mentioned by Polybius in the 2nd century BC in the accounts of the Illyrian Wars and Macedonian Wars. The location of the ancient town is still unknown. It was probably situated between Lychnidus and Antipatrea.
Along with Antipatrea, Chrysondyon and Creonion, Gertus was one of the Dassaretan towns (also described as castella) around which the Illyrian dynast Skerdilaidas and the Macedonian king Philip V fought in 217 BC. The settlement of Gertus was evidently walled.