Objective: This study aims to investigate the effects of tibialis posterior muscle (TP) fatigue on dynamic plantar pressure (DPP) characteristics during different walking speeds. Materials and Methods: Thirty healthy volunteers walked at normal and fast paces in three trials. The Footscan®3D system was used to obtain the distribution of dynamic plantar pressure before and after the TP fatigue protocol. The study measured the peak pressure (PP) of the hallux, toes 2–5, metatarsals (Meta 1-5), midfoot (MF), medial heel (MH) and lateral heel (LH), as well as the percentage of contact area (CA%) of the forefoot (FF), MF and hindfoot (HF), foot progression angle (FPA) and the minimum and maximum values of the subtalar angle. Results: The results showed significant differences in the PP of Meta 4, MH and MF at a normal pace after the tibialis posterior muscle fatigue protocol. At a fast pace, significant differences were found in the PP of the MF and CA% of FF and MF. Before the fatigue protocol, there were significantly different values in the peak pressure of the hallux, toes 2–5 and MH between the two walking speeds. After the fatigue protocol, there were significantly different values in the peak pressure of toes 2–5, MH and LH between the two walking speeds. The study also found a significant difference in FPA between the two walking speeds (p<0.05). Conclusion: The study provides evidence that TP fatigue may lead to injuries during long-term walking or sports activities. These results highlight the importance of endurance training and minimizing its negative effects on foot biomechanics by reducing fatigue.