The electrical resistivity of polymer nanocomposites may be affected by temperature. This characteristic makes them promising materials for temperature sensors for a wide range of applications. High sensitivity, linearity, stability, a wide operating range, and low cost are desirable characteristics for an ideal temperature sensor [1]. Thermocouples exhibit linear behavior, but their comparatively high production cost restricts their applications. Transistor-based temperature sensors have a linear behavior over a wide operating range, but they are associated with drawbacks such as low sensitivity [1]. Alternatively, thermoresistive nanocomposite polymers can be employed for temperature sensing applications. Low production cost and the ease of tailoring their geometry can be listed as the main advantages for this group of sensors. The electrical properties of polymers filled with CNT and GNP have been the subject of extensive research in recent years [2,3,4,5,6,7,8,9,10,11-2,3,4,5,6,7,8,9,10,11]. Several experimental and numerical studies have been devoted to the investigation of the percolation threshold (i.e., the transition between electrical insulator and conductor), electrical resistivity properties, and piezoresistivity effects. However, only a few studies have been conducted to investigate the effect of the temperature on the electrical characteristics of polymeric nanocomposites [1,12,12-14,14-15]. Karimov et al. [16] investigated the effect of temperature on the resistivity and the Seebeck coefficient of a CNT-polymer nanocomposite. Yang et al. [17] studied the effect of temperature on the resistivity of aligned CNT-hydrogel nanocomposites. They showed that the resistance of the composite decreases linearly with increasing temperature. Neitzert et al. [1] demonstrated that the resistivity-temperature behavior of CNT-epoxy nanocomposites can be described by the exponential description developed by Sheng [18] for tunneling conduction in disordered materials. Matzeu et al. [19] developed a temperature sensor based on a CNT/styrene composite. They reported a negative temperature coefficient for the developed sensor. Further, they showed that the sensitivity of the sensor increases as the filler loading is decreasing. Sibinski et al. [20] examined the effect of temperature on the resistivity of CNT filled polymers. Their study indicated that the nanocomposite resistivity-temperature curve exhibits quasi-linear characteristics. To the best of authors' knowledge, only scarce information on numerical or analytical studies devoted to the resistivity-temperature behavior of nanocomposites is available in the technical literature. Consequently, a need exists for suitable modeling approaches, in particular since suitable models will allow for the efficient design and optimization of polymeric nanocomposites for specific temperature sensing applications. These aspects motivated the present authors to conduct an investigation of the resistivity-temperature characteristics of CNT and GNP filled polymers. A 3D continuum MC model was developed, in which randomly dispersed fillers were included in a representative volume element (RVE). In subsequent modeling steps, finite element modeling was employed to evaluate the nanocomposite electrical characteristics and temperature effects.