A WWF file is a document created by SAVE AS WWF, a program used to create .PDF documents that cannot be printed. It may contain the contents of any electronically printable document. WWF files are used for distributing "green-friendly" documents.

The World Wide Fund for Nature (WWF) created the WWF file format to stop unnecessary printing and to increase awareness about the use of paper. The organization has used slogans such as "Think Before You Print" and "Save as WWF, Save a Tree." WWF files are created using the print dialog option "SAVE AS WWF." Also, WWF files prevent user printing by locking document print permissions with a password. SAVE AS WWF can be used to create and open WWF files. The program was initially developed for Mac OS X, but it is now available for Windows as well. WWF files can also be viewed with some Windows and Linux PDF document readers, including Adobe Acrobat. Apple Preview can open WWF files if you first rename the extension to ".pdf." NOTE: SAVE AS WWF has been discontinued and is no longer available for download.