The temperature coefficient (TC) is an essential figure of merit for silicon-based photovoltaic devices. Recently, solar cells using molybdenum oxide (MoOx)-based passivating contacts have attracted much attention due to their potential to obtain excellent performance. TC quantification for these solar cells is therefore of significant interest. In this study, we investigate the temperature-dependent performance of MoOx-based and silicon heterojunction (SHJ) solar cells and determine the TC of the cells’ open-circuit voltage (TCVoc), short-circuit current density (TCJsc), fill factor (TCFF), and efficiency (TC). To gain a deeper understanding regarding the temperature-dependent behavior of the cell performance, the surface passivation and the contact resistivity of the passivating contacts as a function of temperature are also studied. We find that TC of the MoOx-based cell slightly outperforms TC of the investigated SHJ cell and those of other cell structures reported in the literature, mainly due to the favorable TCJsc and TCFF. The superior TCJsc is suspected to result from the more favorable optical properties of MoOx. The favorable TCFF is mainly due to the improvement of the contact resistivity of the MoOx-based passivating contact at elevated temperatures which counterbalances some of the fill factor losses. We also find that the surface passivation of the passivating contacts is improved with temperature. This improvement is pronounced in the case of MoOx-based passivating contact. However, it does not have a strong impact on TCVoc.