GaInP and GaAs being promising materials for large scale photovoltaic applications, the effect of temperature on the electrical parameters of a GaInP/GaAs tandem solar cell has been investigated in this paper. The top GaInP and the bottom GaAs tandem cells were separately simulated using the one dimensional solar simulator SCAPS-1D. The temperature dependency of the solar cell’s characteristics was investigated in the temperature range from 25 to 80°C. The simulation results show that voltage losses within the tandem cell are additive (Top cell and Bottom cell), while the short circuit current density depends smoothly on temperature, and the efficiency reduction is about (-0.038), (- 0.035) and  (- 0.054 % / °C) for the bottom, top and tandem cells respectively. The matching current becomes dependent on the top cell, since this last has smaller variation compared with the bottom cell.