We predicted the electronic structure and half-metallic properties of the Mn₂XSb (X = Co, Fe) inverse Heusler alloys using the full-potential linearized augmented plane wave (FPLAPW) method. We used generalized gradient approximation (GGA) and GGA + U schemes to compute the electronic structure for both alloys. We employed the Tran and Blaha modified Becke– Johnson (TB-mBJ) potential to accurately estimate the band gap. The stability has been determined by calculating their formation energy and elastic constants under ambient conditions. Both alloys show a half-metallic ferromagnetic nature with a 100% spin polarization at the Fermi level. The calculated total spin magnetic moments of Mn₂XSb (X = Co, Fe) alloys are 4μ_B and 3μ_B, respectively, which is a good agreement with the well-known Slater–Pauling rule of 24. The predicted Curie temperature for both alloys is greater than room temperature. The half-metallic and high spin polarization properties make them one of the promising candidates for spintronic device applications.