I know how to set up the parser to not download entities. But I have not found a way to stop XMLCatalog from downloading other xsd's than the root xsd. from lxml import etree parser = etree.XMLParser(no_network=True) xsddoc = etree.parse('schemas/ler/2.0_ler.xsd',parser=parser) xsd = etree.XMLSchema(xsddoc) The above code will recursively download the XSD's imported in 2.0_ler.xsd. I played around with xmllint and I believe that if XML_PARSE_NONET is True, if will not download those. But how do I set that option for the context in which XMLSchema runs? Sincerely, Thomas