Year 165 BC was a year of the pre-Julian Roman calendar. At the time it was known as the Year of the Consulship of Torquatus and Octavius (or, less frequently, year 589 Ab urbe condita). The denomination 165 BC for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years.

• Artaxias I, king of Armenia, is taken captive by the Seleucid king Antiochus IV Epiphanes when he attacks Armenia. Artaxias is forced to recognize Antiochus IV's suzerainty over Armenia before he is released.

• The Roman playwright Terence's play Hecyra (The Mother-in-Law) is first performed.^[1]

• Sima Tan, Chinese astrologist and historian (approximate date)

• Mattathias, Jewish leader of the Maccabees
• Phraates I, king of Parthia (Arsacid dynasty)