Contivo Builder
- XML Schema development tool using a vocabulary design model.
- http://www.contivo.com/builder/builder.html

TIBCO Turbo XML
- Commercial software that provides a design environment for the creation, conversion, and editing of DTDs and various XML schema dialects. Details of features and benefits.
- http://www.tibco.com/software/metadata/turboxml.jsp

XMLFox freeware XML/XSD Editor
- Freeware graphical XML editing and validation tool for creating valid, well-formed XML documents and/or XSD Schema.
- http://www.xmlfox.com

Stylus Studio DTD Tools
- DTD editor, DTD Generation, DTD validation, DTD conversion, and industry standard DTD catalog support.
- http://www.stylusstudio.com/dtd.html

XSBrowser
- Open source browser that creates a human readable document model from a given DTD or XML schema.
- http://www.lumrix.net/xsbrowser.php

xmlDraft
- an intuitive XML Schema editor, displaying a realtime treeview mockup of what the Instance XML Document should look like while editing the XML Schema
- http://www.sysonyx.com/products/xmlDraft/index.asp

Blueprint XML Editor
- XML editor and validator of XML documents, DTDs, Relax NG Schemas and XML Schemas. Provides XSLT transformation and preview in built-in browser. Unicode support.
- http://www.xmlblueprint.com/

oXygen
- XML Editor and XSLT Debugger in Java. Can validate XML, XSD, DTD and XSL. Provides XSLT transformation, Unicode support, FOP support, browser preview, automatic DTD generation, code insight and outliner.
- http://www.oxygenxml.com