Prinicples of sequence stratigraphy were applied to 2D seismic data to study the evolution of a N-S prograding system that developed in the southwestern Barents Sea during Eocene. Four units were interpreted in the basin, of which two progradational units were studied in detail based on reflection terminations. The sequence stratigraphic analysis provides evidence for a change in the beginning of Eocene from a bathyal/marine environment to a depositional environment affected by major clastic sediment input from north. The N-S prograding system was complimented by two additional sediment inputs during Eocene, from the northern part of the Senja Ridge and from remains of an ENE-WSW prograding Paleocene system from east. Several earlier studies have proposed the Loppa High as one of the main source areas of the Eocene succession in the Tromsø Basin, in addition to the Senja Ridge and Stappen High. However, the depositional patterns and geometries observed in this study indicate that the main source area of the Tromsø Basin must have been in the north. The Stappen High is suggested as one of the northern source areas for the Eocene sediments in the Tromsø Basin, but is most likely assembled by at least one additional source area in the north due to the great volumes of Eocene sediments in both the Sørvestsnaget and Tromsø basins. This could be in the uplifted northern Barents Shelf, and/or in the Western Spitsbergen fold-and-thrust-belt that formed in connection to transform movements during the opening of the Norwegian-Greenland Sea and Eurasia basin during Eocene.