The pressure effects on the mechanical, optoelectronic and thermoelectric behaviors of BaSiO3 are studied using DFT based Wien2K code. The mechanical stability is confirmed through the computed Poisson and Pugh ratios, and thermo-dynamical stability is illustrated in terms of calculated negative enthalpy of formation. The band gap is found shifting from indirect to direct nature at the moderate pressure 15 GPa, due to which, phonon heating effects during the optical transitions can be avoided. Optical parameters such as dielectric constants, refraction etc., are discussed for the impinging energy range 0–30 eV. The external pressure dependent electrical and thermal conductivities, power factor, specific heat capacitance, Hall-coefficient etc. are also investigated for 0–800 K. The optoelectronic and thermoelectric natures demonstrate BaSiO3 suitability for the renewable energy device applications. •The impact of pressure is observed on the optical behaviors of BaSiO3.•The use of most advanced computational techniques show technical worth of the study.•Mechanical and thermodynamically stabilities are shown supporting optical applications.•Pressure induced band gap transition and verification of Penn's law are shown.•The optoelectronic and thermoelectric properties show renewable energy applications.