We develop a multiple-view tool called AlViz, which aims at supporting the ontology alignment process visually. Combing views on several levels of abstraction, the tool tries to make the ’relatedness’ between entities accessible. Based on a literature study we identified relevant phases emerging in ontology alignment. We extended a general alignment framework in order to reflect the adoption of visualization techniques. This framework builds the background for our user study. We evaluate visual ontology alignment with AlViz in three stages: (1) Participative software development, (2) usability evaluation, and (3) utility study. The evaluation methods proved viable even though our study design is challenging.