Duchenne muscular dystrophy (DMD) is a muscle wasting disorder caused by mutations in the DMD gene. Restoration of full-length dystrophin protein in skeletal muscle would have therapeutic benefit, but lentivirally-mediated delivery of such a large gene in vivo has been hindered by lack of tissue-specificity, limited transduction and insufficient transgene expression. To address these problems, we developed a lentiviral vector, which contained a muscle-specific promoter and sequence optimized full-length dystrophin, to constrain the dystrophin expression to differentiated myotubes/myofibres and enhance the transgene expression. We further explored the efficiency of restoration of full-length dystrophin in vivo, by grafting DMD myoblasts that had been corrected by this optimized lentiviral vector intramuscularly into an immunodeficient DMD mouse model. We showed that these lentivirally-corrected DMD myoblasts effectively reconstituted full-length dystrophin expression in 93.58±2.17% of the myotubes in vitro. Moreover, dystrophin was restored in 64.4±2.87% of the donor-derived regenerated muscle fibres in vivo, which was able to recruit members of the dystrophin glycoprotein complex at the sarcolemma. This study represents a significant advance over existing cell-mediated gene therapy strategies for DMD that aim to restore full-length dystrophin expression in skeletal muscle.