Assesos or Assesus (Ancient Greek:) was a small ancient Greek town in the region of Caria in Asia Minor, near Miletus, and the site of a sanctuary of Athena. It is mentioned by Herodotus in his Histories (I.18–23) in the context of an episode during the war between the Lydians under Sadyattes and the Milesians in the late 7th century BC, when Lydian troops destroyed the sanctuary. The site of the ancient settlement has been identified by archaeologists at the modern location Mengerevtepe, some 7 km south-east of ancient Miletus.