Doberdò del Lago is a comune (municipality) situated in the Friuli-Venezia Giulia region of northeastern Italy. It is located within the regional decentralization entity of Gorizia, positioned approximately 30 kilometres northwest of Trieste and about 11 kilometres southwest of Gorizia.
The municipality is situated in the westernmost portion of the Karst Plateau. It shares borders with several neighboring municipalities, including Duino-Aurisina, Fogliano Redipuglia, Monfalcone, Ronchi dei Legionari, Sagrado, and Savogna d'Isonzo, as well as the Slovenian municipalities of Komen and Miren-Kostanjevica.