Oil-in-water nano-emulsion adjuvant (NEA) has been utilized for many years in the development of subunit or/and recombinant vaccines. Nevertheless, worries have been expressed about the safety and potential biological activities of the emulsifier. Herein, tocopheryl polyethylene glycol 1000 succinate (TPGS), which acts not only as an emulsifier but also as an immunostimulant, was used for the preparation of NEA. Benefiting from the hydrophilic-hydrophobic nature of TPGS, NEA possess a homogeneous structure with an extremely narrow size distribution (approximately 160 nm in diameter, polydispersity index <0.15), and exhibits excellent stability over 6 months under test conditions. When such an NEA was used with a recombinant respiratory syncytial virus (RSV) vaccine, the adjuvanted vaccine induced enhanced humoral and cellular immunity in mice compared to the non-adjuvanted vaccine. This is the initial documented finding of TPGS adjuvanticity in an intramuscularly injected vaccine. Furthermore, the TPGS-based NEA showed elevated adjuvant potency compared to the MF59-like emulsion adjuvant assessed. These results imply the potential of NEA as an alternative adjuvant for developing recombinant vaccines with enhanced immunity.