Wear is a phenomenon that is encountered in most mechanical systems with moving parts. It is directly related to the life and reliability of the system, and hence, wear should be controlled in order to achieve the desired life and performance of the system. Due to the complex nature of wear, understanding of the mechanisms of wear is still lacking. The extent and characteristics of wear depend on the scale of the system which is largely dictated by the load applied between the components in contact. Particularly, in nano-scale, the mechanisms of friction and wear are unclear and often elusive. As such, the development of microsystems technology is hindered by the challenges of surmounting the friction and wear problems at the nano-scale. In this paper advancements made in the field of nano-wear are reviewed with the aim to provide an overview that can be useful to engineers and scientists who are not necessarily in the field of tribology. Research works conducted using AFM to probe the nano-scale wear of ultra-precision components are discussed. The works related to nanotribology of MEMS are also reviewed. In addition to the experimental investigations, theoretical and simulation works regarding nano-wear at the atomic-scale are introduced.