Tensor fasciae suralis (TFS) is an accessory muscle of the posterior lower extremity. Although TFS has been documented in cadaveric and radiological reports, its prevalence remains unknown. The TFS variant is noteworthy to anatomists, as it may be encountered in the dissection laboratory, and clinicians, as the muscle could potentially cause confusion during physical examination or diagnostic imaging. Multiple variations of TFS have been reported in the literature, suggesting the need for a classification system. We dissected 236 formalin-fixed cadaveric lower limbs to determine the prevalence of TFS. The PubMed and MEDLINE databases were searched to compare the anatomical features of independent TFS case reports. In our prevalence study, the TFS muscle was identified in three lower limbs (1.3%). In total, 38 cases of TFS (32 cadaveric and six radiological) were identified in the literature. Our literature review revealed that the accessory muscle most often arises as a single head from the long head of the biceps femoris, yet many other presentations have been documented. The need for a classification system to distinguish between the subtypes of TFS became apparent during the literature review. Tensor fasciae suralis is a rare muscle, present in only 3 of 236 (1.3%) cadaveric lower limbs dissected in this study. We propose the use of a classification system, based on muscle origin and number of heads, to better organize the subtypes of TFS.