A physics-based temperature-dependent yield strength model without fitting parameters was developed for single-phase FCC high-entropy alloys. The model considered the temperature dependence of lattice friction stress, solid solution strengthening, grain boundary strengthening, dislocation strengthening, and their evolution with temperature to the overall yield strength. The results show that a quantitative relationship between temperature, material parameters, and yield strength was successfully captured by the model. This model can predict the yield strength at different temperatures only by using the easily available material parameters at room temperature. The accuracy of model was well verified by 17 sets of available experimental data over a wide temperature range (4.2-1273 K). Moreover, the contribution of different strengthening mechanisms to the yield strength was quantitatively analyzed and discussed from 4.2 to 1273 K, and some suggestions for improving the temperature-dependent yield strength were put forward.