Based on studies of shore levels and lake sediments, a change in outlet from the eastern to the western end of lake Jølstravatnet is demonstrated. The change was caused by the faster uplift in the eastern end. The lake history is subdivided into five phases. During phase I ( -9500 BP) lake Jølstravatnet was an ice-dammed lake. During phases Il and Ill (9500-7500 BP) there was an eastern outlet and glacioisostatic tilting caused a transgression in the western part of the lake until the lake leve) had risen to the threshold in the western end. Phase IV (7500--6000 BP) is characterized by outlets at both ends of the lake. The emergence of the eastern outlet (ca. 6000 BP) marks the transition to phase V, i.e. the present situation, with an outlet over the western threshold. By making a tentative comparison between the Jølstravatnet time-gradient curve and two marine based curves from adjacent areas some trends in the glacioisostatic rebound of western Norway are deduced.