The long‐term thermal stability of Dye‐Sensitized Solar Cells (DSSCs) is a major challenge that needs to be addressed for this technology to become commercially viable. In this work, we investigate the effect of incorporating multi‐walled carbon nanotubes (MWCNTs) on the thermal stability of DSSCs. Under identical measurement conditions (aging at 80 °C for 240 h in the dark), DSSCs based on a bare TiO2 anode present a significant loss in photo conversion efficiency (PCE), dropping to 59% of their initial value, while the DSSCs based on a TiO2‐MWCNTs nanocomposite anode attained a promising thermal stability with only 20% reduction of the initial PCE. This loss in cell performance is mainly associated with a dramatic reduction of the short circuit current density (Jsc) upon thermal aging. To understand the degradation mechanisms under thermal stress, both types of cells were investigated by field emission scanning electron microscopy (FESEM), Raman spectroscopy and electrochemical impedance spectroscopy (EIS). The incorporation of MWCNTs could eliminate the formation of cracks and improve electron charge transfer. The results of this work indicate a new promising method to enhance the thermal stability of DSSCs using a nanocomposite anode made of one‐dimensional carbon materials.