This study aims to use Bouguer gravity anomalies to create a simple subsurface model of the southeastern Thrace Basin, a Tertiary depositional area located in the Northwest Turkey. Relative gravity data have been collected at over 500 points in the study area, converted into Bouguer gravity anomalies and combined with the Bouguer gravity data available in the literature for the area. The study area is subdivided into eight geological units depending on the ages and densities. A total of 12 gravity profiles were deduced from the gravity map and modelled using 2D structure, then combined into a 3D subsurface model. The observed and the calculated gravity data are highly synchronous with an RMS of ~ 0.2 mGals. Results indicate that the basin has an approximate depth of 4000 m. These findings do not agree with the other studies in literature, which will be discussed. The produced model is the most detailed shallow subsurface model of the area so far, consisting of multiple geological layers.