The rapidly advancing field of lipid-based nanoparticles (LNPs) as delivery systems for nucleic acids has the potential to revolutionize treatment strategies. LNPs have demonstrated exceptional versatility in delivering genetic material and therapeutic agents to target cells. In gene and cell therapy, LNPs could serve as efficient carriers for introducing genetic materials into the cells, addressing inherited genetic disorders at their root. Their minimal toxicity and immune response make them particularly suitable for pediatric applications. Additionally, the scalability and cost-effectiveness of LNP production offer practical advantages over methods such as viral vectors and electroporation (EP), improving accessibility to advanced therapies for children worldwide. In 2018, the first FDA-approved LNP-based siRNA therapy (Patisiran/ Onpattro®) for treating hereditary amyloidosis brought attention to the feasibility of LNPs for gene therapy. Eventually, authorization and approval of the mRNA-LNP vaccines against COVID-19 (Comirnaty® of BioNTech/Pfizer and SpikeVax® of Moderna) was another milestone for the development of LNP-based nucleic acid therapies. Later, LNPs were applied successfully for the delivery of pDNA, mRNA and siRNA in many types of genetic disorders and cancers. This innovative approach offers a brighter future for pediatric healthcare, where children can look forward to healthier and more fulfilling lives. This review paper provides an overview of the applications of LNPs in gene and cell therapies with a special focus on their pre-clinical application in primary cells, including natural killer cells, T cells, and hematopoietic stem cells, highlighting LNPs’ efficacy, safety profile, and potential for transforming the landscape of pediatric healthcare in the future.