We investigate the electronic structure, elastic, optical and thermoelectric properties of single-perovskite BaTbO3 by means of the density functional theory approach employing generalized gradient approximation and an on-site coulomb potential. The calculated lattice constants are found to be in good agreement with the available experimental results. The elastic property calculations reveal that BaTbO3 is mechanically stable and ductile in nature. The spin polarized density of states and band structure calculations shows a semiconducting state with band gap ~ 1 eV with anti-ferromagnetic ground state. Based on the obtained values of optical parameters, BaTbO3 is found to be optically active both in the ultra-violet and visible region of the spectrum. Furthermore, thermoelectric properties are evaluated by using BoltzTraP code based on Boltzmann transport theory employing constant relaxation time and rigid band approximation in the temperature range 300 – 1200 K. The noticeable value of power factor is observed at higher temperature region with the maximum value ~ 12 μWcm−1K−2 at 1200 K and the lattice thermal conductivity is significantly low in the entire temperature range. The maximum value of ZT found to be ~ 0.35. The results reveal that this compound can be used as a good optoelectronic application as well as thermoelectric material in the high temperature region.