Research emphasizes in face recognition has shifted towards recognition of human from both still images and videos which are captured in unconstrained imaging environments and without user cooperation. Due to confounding factors of pose, illumination, image quality, and expression, as well as occlusion and low resolution, current face recognition systems deployed in forensic and security applications operate in a semi-automatic manner. This book chapter presents a comprehensive review of face recognition approaches in unconstrained environment. The objective of this book chapter is to address issues, challenges and recent advancement in face recognition algorithms which may help novel researchers to do innovative research in unconstrained environment. Finally, this chapter provides the stepping stone for future research to unveil how biometrics approaches can be deployed in unconstrained face recognition systems.