Abstract The incised coastal valley fill of the Mono and Oueme Rivers in Benin comprises several Late Pleistocene and Holocene facies that have been interpreted in sequence-stratigraphic terms. The study shows the existence of lowstand, transgressive and highstand systems tracts related to the last 120,000 year eustatic cycle and the subsequent still-stand since around 5500 BP. The lowstand systems tract consists of Late Pleistocene alluvial sediments overlying an earlier sequence in the Oueme valley. This tract has not been identified in the Mono Valley mouth where the lower sequence boundary directly separates the transgressive systems tract from the underlying substratum. The transgressive systems tract is represented by lagoonal mud and bay-mouth shoal/flood-tidal delta sands. This tract may also subsist as a thin shoreface lag or overwash sandy gravel deposit. The lagoonal muds are separated in places from the overlying estuary-mouth sands by tidal or wave ravinement surfaces. The highstand systems tract comprises the following: prograded sand barrier beach/shoreface sands, a non-prograding barrier associated with a migrating inlet, lagoonal muds and bay-head delta sands and muds. This tract has been partly reworked by tidally-influenced migration of the Mono channel and includes highstand fluvial-tidal, tidal and wave ravinement surfaces. Fine-scale differentiation of early highstand and late transgressive systems tracts and the maximum flooding surface, especially in the Oueme Valley, is rendered difficult by the essentially similar nature of their facies. This is notably the case of muddy backbarrier lagoonal sediments. It is hoped that future work will enable a finer resolution of these sequence tracts and stratigraphic surfaces.