In the present study, the thermoelectric properties of tetragonal iron antimonide FeSb2 have been performed by the all-electrons full-potential linearized augmented plane wave (FP-LAPW) method within the framework of Density Functional theory (DFT) combined with semi-classical Boltzmann transport theory through BoltzTrap code. Based on Generalized Gradient Approximation as parameterized in Perdew, Burke, and Ernzerhof (PBE-GGA) was employed to calculate the exchange–correlation potential. The plotted Seebeck coefficient, electronic thermal conductivity, electrical conductivity, electronic specific heat, magnetic susceptibility, Hall coefficient, and figure of merit in the temperature range from 10 to 800 K are obtained and discussed.The metallic nature of the iron antimonide compound is confirmed by its low Seebeck coefficient values, the linear increase in thermal conductivity with rising temperature, and the significant drop in electrical conductivity within the 0–110 K temperature range. The positive magnetic susceptibility values suggest that this material is paramagnetic. The key findings of this study reveal that the high electrical conductivity of FeSb2 makes it suitable for use as an anode in lithium-ion batteries. Additionally, the calculated transport properties suggest that FeSb2 is a promising material for thermoelectric engineering applications.