We propose a generic approach for the adaptation of user interfaces to the accessibility context. This approach is based on the Model-Driven Engineering MDE. Thus, we adapt any kind of UI to the accessibility context based on a generic adaptation process. We are based on meta-model transformations parametrized with the context of accessibility. The proposed approach generates modality-based UI adapted to each disability. We have developed an accessibility context related to the type of disability, the used platform, the user identity and his/her situation, the surrounded environment and modelled into ontology. The metamodel transformations were based on mapping rules implemented by the Kermeta language.