Techniques and tools are described for converting XML documents and XML schema documents to OWL. An OWL model ontology can be generated by receiving XML schema documents, performing schema consolidation, and generating the OWL model ontology from the consolidated XML schema. An OWL instance ontology can be generated by receiving XML documents and XML schema documents and generating an OWL instance ontology from the XML documents and the XML schema documents. OWL model extraction and OWL instance generation can be performed in parallel and without the need for intermediate XSLT documents. Schema consolidation can comprise collecting schema documents, merging schema documents, and reorganizing the merged schema document to create a consolidated schema document.