Gaucher disease (GD) is an autosomal recessive lysosomal storage disorder caused by mutations in the GBA gene. Enzyme replacement treatment is the most effective therapy available for type 1 GD patients, but it is very expensive and does not improve neurologic outcomes in type 2 and 3 GD patients. This study evaluated the effectiveness of an adeno-associated virus 9 (AAV9) vector expressing the Gba gene delivered systemically in GD mouse models. To detect the therapeutic effects of the AAV9-mediated Gba transfer on the systemic symptoms of GD, an inducible whole-body Gba knockout mouse was developed in which tamoxifen effectively induced whole-body Gba gene deletion, and the mice displayed systemic symptoms of GD. The AAV9-CMV-Gba vector, with the expression of Gba driven by the universal CMV promoter, restored GCase activity in multiple organs and prolonged the lifespan in tamoxifen-induced GD mice after intravenous injection. Mice with brain-specific Gba deletion were also included in this study as a model of neuropathic GD (nGD) and injected intraperitoneally on postnatal day 5 with the AAV9-SYN-Gba vector; this improved the GCase activity, ameliorated the neuropathological changes and extended the mean lifespan two-fold. This study demonstrates that AAV9-mediated gene transfer is a potentially effective treatment for GD.