Parallel to growth of the Internet, social networks have become more attractive as a research topic in many different disciplines and many real systems can be denoted as a complex network. Identifying major clusters and community structures allow us to expose organizational principles in complex network such as web graphs and biological networks. It has been shown that communities are usually overlapping. Overlap is one of the characteristics of social networks, in which a person may belong to more than one social group. In recent years, overlapping community detection has attracted a lot of attention in the area of social networks applications. Many methods have been developed to solve overlapping community detection problem, using different tools and techniques. In this paper, one of the most recent social-based metaheuristic algorithm, Parliamentary Optimization Algorithm (POA), has been firstly proposed to discover overlapping communities in social networks.