We introduce a multiple-view tool called AlViz, which supports the alignment of ontologies visually. Ontologies play an important role for interoperability between organizations and for the semantic web because they aim at capturing domain knowledge in a generic way and provide a consensual understanding of a domain. Alignment is the process where for each entity in one ontology we try to find a corresponding entity in the second ontology with the same or the closest meaning. Existing ontology alignment tools do not adequately provide a way for users to analyse the results. While many alignment tools generate lists of mappings it is difficult to analyse these alignments without examining every pairwise correspondence in the output files and even then it is an overwhelming task. We propose the use of visualization techniques to facilitate user understanding of the ontology alignment results. AlViz is implemented as a tab plug-in for Protege.