Landscape evolution studies enable us to understand site formation processes affecting past hunter-gatherer settlements. This work presents a landscape reconstruction of Roca dels Bous site (RB), which is a reference site for the Late Mousterian occupation of the incised valleys of the southeastern Pyrenees. For this purpose, we combined geomorphological studies, stratigraphic descriptions, new single-grain optically stimulated luminescence datasets, statistical methods, and geophysical surveys. RB formed by gravitational processes induced by fluvial undermining of the Segre River during changing late Pleistocene climatic conditions. Geomorphological and chronological data combined with fluvial age-incision models suggest that, during Late Mousterian occupation, RB was located very near the Segre floodplain level and closer to water and raw material natural resources than at present. The accumulation of gravitational deposits associated with the archaeological levels occurred at rates of 0.16–0.44 m ka-1, between 55 and 47 ka, coinciding with Marine Oxygen Isotope Stage 3 (MIS3). More detailed comparison with available climatic curves suggests that the dated RB layers were potentially deposited during cold phases within MIS3. This work provides new landscape-based evidence to examine the paleoenvironmental context of Neanderthal presence in the southeastern Pre-Pyrenees, an important region in the debate regarding Neanderthal demise in Western Europe around 40 ka.