Neuronal ceroid lipofuscinosis type 2 (CLN2 disease) is a progressive neurodegenerative disease characterized by early-onset progressive neurological and vision-related disabilities, leading to death in late childhood. Management has previously relied on symptomatic and palliative care, but the approval of the enzyme augmentation therapy cerliponase alfa in the USA and Europe in 2017 and various gene therapy strategies being tested in the clinic has given hope to the CLN2 community. Intraventricular administration of cerliponase alfa, the enzyme augmentation therapy, results in significant reductions in the rate of decline of motor and language functions in comparison with a natural history population but requires administration twice monthly at specialized clinical centers. The promise of gene therapy is that a single administration should theoretically provide sufficient TPP1 to the CNS or the eye to correct the deficiency state. This promise has been partially met by an intraparenchymally administered AAV-mediated gene transfer of the CLN2 gene, but there is a need for further optimization of dose, route of administration, age of administration, and larger size study cohorts. It is expected that effective gene therapy will lead to a successful single administration therapy for the life of the patient, with improved quality of life. In this review, we detail the state of the art in gene therapy for CLN2 disease, assess the status, and summarize the challenges that need to be overcome to make CLN2 gene therapy successful.