Vertically aligned ZnO/CdTe core/shell nanowire arrays have been grown by low-cost deposition techniques. ZnO nanowires have a wurtzite structure and are c-axis oriented. The CdTe shell completely covers ZnO nanowires and consists of nanograins, which are slightly oriented along the ⟨111⟩ direction owing to a grain growth process driven by surface energy minimization. Their nucleation follows the Volmer–Weber growth mechanism: in particular, island coalescence results in the generation of high tensile stress, which significantly reduces the CdTe optical band gap. Furthermore, both ZnO and CdTe exhibit excitonic emission bands around 3.36 eV and 1.56 eV, respectively.