Abstract: During the past few years, face recognition techniques has received a significant attention. Face recognition is considered a non-threatening, natural and commonly accepted biometric technique. These techniques depend on the analysis of frontal or profile images of the face that are often effective without the participant’s cooperation. In this study, face recognition techniques are discussed and reviewed in two different sections and have gone some way towards enhancing our understanding of the various approaches applied for face recognition and their advantages and disadvantages to date. This study, provides an up-to-date investigation of face recognition researches as regards to 2D and 2.5D image based face recognition techniques. As a result, this study, suggests compensating for the problems and the limitations of 2D based image techniques by substituting them with 2.5D range images because 2.5D approaches have proven themselves to outperforming 2D based image approaches. To validate this study, a set of experiments using OPSO-SVM face recognition technique are applied on a property 2.5D face dataset.