We have studied the structural, electronic, and lattice dynamics properties of ${\mathrm{Nb}}_{1\ensuremath{-}x}{\mathrm{Mo}}_{x}$ alloy within the framework of density functional theory using the self-consistent virtual-crystal approximation (VCA). The structural properties, electronic band structure, and selected high-symmetry phonon frequencies have been calculated for the entire range of Mo concentrations comparing two implementations, an all-electron and a pseudopotential method. We found very good agreement between both methodologies for all calculated properties, independent of the approximation used for the exchange-correlation functional. We identified an electronic topological transition for this alloy at around 30% of Mo content. For all properties considered, we found good agreement with experimental results, indicating the applicability of the VCA for this alloy.