In this work thermoplastic polyurethane (TPUs) nanocomposites incorporating carbon nanotubes (CNTs) were prepared via melt blending and compression molding and their physical and mechanical properties were characterized. TPU-CNT systems exhibited extensive filler agglomeration, which resulted in a significant decrease in strength and ductility. Since shear mixing was not effective enough to disentangle CNTs during melt mixing, surfactant was combined with the CNTs via ultra-sonication. TPU-CNT surfactant nanocomposites exhibited significantly enhanced tensile properties and viscoelastic behavior comparing with nanocomposites prepared without surfactant, thanks to the more homogeneous filler dispersion, as indicated by scanning electron microscopy (SEM). Thermogravimetric analyses (TGA) shed some light on a second mechanism of improvement in the mechanical properties: the well-dispersed nanofillers can also favor higher phase separation in the TPUs, leading to a better microstructure able to enhance load transfer and maximize system mechanical properties. Synergistic effects were observed when 1D-CNTs were combined with 2D-graphene nanoplatelets (GNPs) in TPU hybrid composites. Enhanced tensile properties and viscoelastic behavior were observed with respect to the systems incorporating individual CNTs and GNPs, especially when combining GNPs and CNTs at a ratio of 6:4. Hybrid (6:4) nanocomposites also exhibited the best creep resistance and recovery ability, since the network formed by 1D-CNTs and 2D-GNPs can hinder the movement of TPU chains, leading to a decrease in viscoelastic and viscous deformation [1]. The synergistic mechanism was hypothesized to occur due to the combination of two fillers with different shape and aspect ratio, with the long tortuous CNTs limiting GNPs aggregation and bridging adjacent graphene platelets in order to form a more efficient 3D network [2].