Dolutegravir (DTG) is an antiretroviral drug approved in the year 2013, and being categorized as a BCS-II molecule, it possesses solubility issues. In order to enhance the solubility and improve its bioavailability, DTG-loaded Chitosan nanoparticles (NPs) were synthesized utilizing spray drying technology. The developed nanoformulation was characterized for its physicochemical properties and investigated for the feasibility of its administration through an oral route along with milk/food as an admixture for paediatric antiretroviral therapy. The in vivo oral bioavailability studies were conducted in Balb-C mice, where the animals were treated with the selected formulation of DTG-loaded Chitosan NPs and compared to pure DTG. The NPs exhibited 2.5-fold increase in the Cmax (77.54 ± 7.93 μg/mL) when compared to the pure DTG (30.15 ± 8.06 μg/mL). This phenomenon was further reflected by the improved bioavailability of DTG (AUC: 678.3 ± 10.07 μg/h/mL) in the NPs administered to mice when compared to the AUC of animals administered with pure DTG (405.29 ± 7 μg/h/mL). Altogether, the research findings showed that Chitosan-based NPs were ideal carriers for oral administration of DTG along with milk and exhibited great potential to enhance the bioavailability of the drug and treatment adherence for paediatric HIV patients.