Wikis have proven to be an invaluable tool for collaboration. The most prominent is, of course, Wikipedia. Its open nature is not suitable for all environments; in corporate, government, and research environments it is often necessary to control access to some or all of the information due to confidentially, privacy, or security concerns. This paper proposes a method by which information classified at multiple sensitivity levels can be securely stored and made accessible via the wiki only to authenticated and authorized users. The model allows for each page to be viewed at appropriate levels of classification transparently included or excluded based on the user's access level. Categories and Subject Descriptors I.7.5 [Computing Methodologies]: Document and Text Processing; K.6.5 [Computing Milieux]: Management of Computing and Information Systems--Security and Protection General Terms Design, Security Keywords Redaction, Multilevel Security, Collaboration