Today, the Internet and the Web are the most amazingly and dynamically growing computer technologies. The number of users accessing the Web is growing exponentially all over the world. The Web has become a popular environment for new generation of interactive computer applications called Web (or hypermedia) application. The Web applications (WAs) have special characteristics that have made them different from other traditional applications. Hence, many design methodologies for the development of WAs have been proposed. However, most of these methodologies concentrate on the design aspects of applications, and they often do not strictly follow any software development life-cycle model such as the WaterFall software development life-cycle model. In this chapter, we propose an object-oriented design methodology for the development of WAs. The main features of this proposed methodology are that it follows WaterFall model and captures the operations in objects of the applications; thus making the methodology an object-oriented methodology.