In this work, pure barium titanate (BT) and cobalt doped barium titanate (CBT) were synthesized by using barium chloride, tetrabutyl titanate, cobalt chloride, and titanium chloride as precursors via a two‐step hydrothermal process. These precursor mixtures were further blended with a dispersion of surfactant + graphene nanoplatelets (GNP) judiciously during the second step of hydrothermal process to obtain their respective BT‐GNP and CBT‐GNP nanocomposites. The morphological and crystal structures of BT, CBT, BT‐GNP, and CBT‐GNP samples were analyzed by the powder XRD, and FESEM revealed that the formations of 10‐ to 30‐nm‐sized cubic phase BT, CBT nanoparticles with least amount of agglomerations, and more spherically shaped particles in the CBT, whereas their nanocomposite morphologies and compositional elemental mapping showed random distributions of BT and CBT particles over the GNP. The FT‐IR analysis indicated the presence of strong chemical interactions between the nanoparticles and GNP sheets in both the BT‐GNP and CBT‐GNP nanocomposites. Furthermore, the dielectric measurements carried out on the BT, CBT, BT‐GNP, and CBT‐GNP samples showed tremendous influences of metal doping and GNP on the BT which can support to tune its dielectric properties for several storage applications.