There has been a growing need to for forensic anthropologists to determine the age of living individuals in the absence of documentation. Often, it is of vital importance to legal proceedings to determine if an individual meets particular age criteria, particularly the age of 18 years which is the legal age of majority in many countries. The age estimation potential of the dentition and various elements of the post-cranial skeleton, particularly the hand-wrist and clavicle, have been well demonstrated and are widely accepted for forensic use. Less often discussed is the age estimation potential of the knee, which is easy to image and has been validated through a number of studies. This review provides an overview of the current scholarship regarding the age estimation potential of the knee, and outlines possible future directions for further research.