This study investigates the structural, elastic, optical, and electronic properties of Ba2MBiO6 (M=Sm, Tb) oxide double perovskites using Density Functional Theory (DFT) within the Wien2k software. The generalized gradient approximation (GGA) is used for structural and elastic properties, while the Tran-Blaha modified Becke-Johnson (TB-mBJ) potential is employed for optical and electrical properties. The Birch-Murnaghan equations of state and tolerance factors are used to verify the structural stability of both compounds. Both systems are found to be elastically stable and exhibit anisotropic ductile and ionic bonding behavior. Ba2SmBiO6 is a non-central force crystal with a volume ratio (v) of 0.51, while Ba2TbBiO6 is a central force crystal with v = 0.29. Ba2SmBiO6 shows half-metallic behavior with spin-dependent band gaps, making it a potential candidate for spintronic applications. Ba2TbBiO6 behaves as a direct band gap semiconductor with a 1.79 eV band gap. Both compounds have optical properties in the UV-visible region, indicating potential for optoelectronic applications. The study aims to provide reference data for experimental investigations in this field.This study investigates the structural, elastic, optical, and electronic properties of Ba2MBiO6 (M=Sm, Tb) oxide double perovskites using Density Functional Theory (DFT) within the Wien2k software. The generalized gradient approximation (GGA) is used for structural and elastic properties, while the Tran-Blaha modified Becke-Johnson (TB-mBJ) potential is employed for optical and electrical properties. The Birch-Murnaghan equations of state and tolerance factors are used to verify the structural stability of both compounds. Both systems are found to be elastically stable and exhibit anisotropic ductile and ionic bonding behavior. Ba2SmBiO6 is a non-central force crystal with a volume ratio (v) of 0.51, while Ba2TbBiO6 is a central force crystal with v = 0.29. Ba2SmBiO6 shows half-metallic behavior with spin-dependent band gaps, making it a potential candidate for spintronic applications. Ba2TbBiO6 behaves as a direct band gap semiconductor with a 1.79 eV band gap. Both compounds have optical properties in the UV-visible region, indicating potential for optoelectronic applications. The study aims to provide reference data for experimental investigations in this field.