The structural, electronic, and thermoelectric properties of DO₃ V₃Al in the paramagnetic (PM) and antiferromagnetic (AF) phases are investigated using the semi-classical Boltzmann theory in combination with deformation potential theory from first-principles calculations. The structural results are consistent with other theoretical and experimental data. AF-DO₃ V₃Al is verified to be a gapless semiconductor. Based on the calculated relaxation time τ and lattice thermal conductivity κ_L, the thermoelectric properties of PM-DO₃ and AF-DO₃ V₃Al have been predicted. Compared with PM-DO₃ V₃Al, the AF-DO₃ phase exhibits favorable thermoelectric performance. The optimized thermoelectric figure of merit ZT of the p-type AF-DO₃ phase can be as high as 0.32 at T = 500 K. It is possible to make V₃Al a promising candidate for efficient thermoelectricity by reducing its thermal conductivity.