Early and middle Holocene sea-level data from Belgium plot ca. 2 m above data from the western Netherlands, reflecting differential tectonic and isostatic movements. The total uplift rate of Belgium relative to the western Netherlands decays gradually from 0.66 m kyr-1 at 7500 cal. yr BP to less than 0.25 m kyr-1 since 5000 cal. yr BP. The tectonic component of this relative movement, inferred from Eemian sea-level data, is in the order of 0.06 to 0.16 m kyr-1. The isostatic component of the uplift is related to the last phase of the collapse of a peripheral bulge under The Netherlands and the Dutch and German sectors of the North Sea, and to hydroisostatic subsidence of the North Sea basin caused by water loading as sea-level rose. Comparisons with isostatic rebound models show that they predict well the Holocene isostatic movement between Belgium and the western Netherlands, and that the predictions are improved when the tectonic component is removed from the observations. Preliminary evaluation of sea-level data from the Dutch sector of the North Sea shows that glacio-hydroisostatic subsidence relative to Belgium was significantly greater than for the western Netherlands coastal area, and spatially highly variable.