NASICON-type Na4MnV(PO4)3 with reduced graphene oxide (rGO) has been synthesized by the simple sol-gel reaction and characterized by different analytical techniques. The resulted material has been explored as a cathode material for rechargeable non-aqueous and aqueous sodium-ion batteries. In non-aqueous electrolytes, the as-synthesized Na4MnV(PO4)3-rGO composite shows stable discharge capacity of 86 mAh g−1 at 0.1 C and 68 mAh g−1 at 0.2 C after 100 cycles in half-cell and full-cell configurations, respectively. In aqueous electrolytes, it delivers an initial discharge capacity of 92 mAh g−1 at 1 C rate in half-cells and 97 mAh g−1 at 10 C rate in full-cells having NaTi2(PO4)3-MWCNT as the anode. Stable cycleability and high rate capabilities of Na4MnV(PO4)3-rGO composite can be attributed to the very strong and sustainable conductive percolation networks for both electrons and Na+ ions. The obtained results reveal that the aqueous electrolyte cell has a huge scope for gird level energy storage applications.