Business support systems (BSS) are the components that a telecommunications service provider (or telco) uses to run its business operations towards customers.
Together with operations support systems (OSS), they are used to support various end-to-end telecommunication services (e.g., telephone services). BSS and OSS have their own data and service responsibilities. The two systems together are often abbreviated OSS/BSS, BSS/OSS or simply B/OSS.
The initialism BSS is also used in a singular form to refer to all the business support systems viewed as a whole system.