Spectral variations of gravity and topography data show nonisostatic compensation of elevation in the Southeast Carpathians that is consistent with our new residual topography calculations. Multidimensional thermomechanical models are created to consider a possible mantle flow component of the surface topography with varying temperature models and crustal configurations. The temperature anomalies derived from large‐scale P wave velocity anomalies and combined temperature model are estimated as input for the parametric numerical modeling experiments. Model results show that a surface uplift (up to ~1 km) develops in the southeastern Carpathians due to the rising hot upper mantle beneath the region. The upwelling flow is also in concordance with observations such as volcanism and enhanced surface heat flow in the region. Subsidence in the eastern part (0.5–1 km over the Vrancea zone and the Focsani Basin) forms in relation to the downgoing Vrancea slab. The findings indicate the significant role of upper mantle structures on the present‐day anomalous topography related to proposed postcollisional tectonics in the Southeast Carpathians.