The Mobile Ad Hoc Network (MANET) is a collection of self-organized mobile nodes that can form a dynamic infrastructure and establish wireless communication among them. The MANETs have gained popularity in many applications like civil and military surveillance due to their inherent characteristics, such as self-organized capability and ease of deployment. In recent years, the MANETs also have to support many real-time multimedia-based applications which require strict Quality of Services (QoS) like delay and reliable data delivery. This paper presents a common overview of MANET characteristics, applications, and QoS requirements. Further, it comprehensively reviews different QoS routing protocols with their advantages and disadvantages. Moreover, this paper discusses the issues in conventional works and the possible future work extensions.