Coupling measures capture the degree of interaction and relationships among source code elements, such as classes, methods and attributes in object-oriented software systems. One of the main goals behind object oriented analysis and design is to implement a software system where classes have low coupling among them. Coupling describes the interrelationship between the various functionalities in a software system. High coupling is a considered as a characteristic of poorly designed system while low coupling is considered as a characteristic of a well-designed system. This paper presents a review of existing coupling measures and classifies them on the basis of class consideration, object considerations and static and dynamic behavior consideration.