OSS may refer to any of the following:
1. Short for Open-source software, OSS is a software source code that is freely distributed to help develop the software or allow for customization with the software. Perl is a good example of an OSS software program. Unlike freeware, open-source software allows any user to modify the code.
2. Short for operations support systems, OSS are automated systems developed by the telecommunications industry to assist customers with services such as billing and maintenance.