File Extension OTF File Format OpenType Font OTF stands for OpenType Font. This was last updated in March 2012 By Margaret Rouse Browse File Extensions Alphabetically: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z # Ask a Question. Find an Answer. Ask your peers a question about this file extension. Ask a Question Add new fonts to files Can't add the .ttf fonts to "add fonts to library" in Suitcase Fusion 6 Which font should be used with unicode and without unicode?