The impact of readout temperature on background during optically stimulated luminescence (OSL) measurement is reported in this study. The background signal on un-irradiated phosphors has been found to increase significantly with readout temperature for the samples studied in this work, Al2O3:C and CaSO4:Dy. This increase in background signal with rising stimulation temperature on un-irradiated phosphors may overlap with the thermally assisted OSL (TA-OSL) signal. This phenomenon was observed only in the case of phosphors and not with bare stainless steel (SS) discs/planchets, and hence, this background emission should not be confused with blackbody radiation. Moreover, the reported background emission was seen to be much larger than the blackbody radiation. Although the TA-OSL signal does increase with temperature, it does not increase proportionally to the background signal. Therefore, to determine the net increase in TA-OSL due to the rise in readout temperature, the increase in background signal should be taken into consideration.