Although Accessibility has not yet gained much recognition as a crucial non-functional requirement like security, performance, accuracy and usability, it is a vital attribute for people with disabilities. Developing accessible Web applications is usually hard for several reasons. Firstly, there is a significant knowledge gap between developers and Accessibility specialists. Secondly, there is little evidence of design approaches dealing with Accessibility from the beginning of the design process. In most cases, Accessibility is regarded as a programming issue or even dealt with when the Web application is already fully developed. Consequently, the process of making this application accessible involves significant redesign and recoding, which might be out of the scope of the project and/or hardly affordable. In this paper, we present an aspect-oriented approach to handle the non-functional, generic and crosscutting characteristics of the Accessibility concerns. Our approach is supported by several techniques, which are embedded in a software tool aiming at facilitating transferring the approach to industry.