The Communications Act says that OfCom's primary duty is to further the interests of citizens and of consumers, where appropriate by promoting competition. Meeting this duty is fundamentally what they do in everything they work on. Accountable to Parliament, OfCom set and enforce regulatory rules for the sectors for which they are responsible for. OfCom also have set powers to enforce competition law in those sectors, alongside the Competition and Markets Authority. The Office of Communications is funded by fees from industry for regulating broadcasting and communications networks, and grant-in-aid from the Government.

OfCom's main legal duties to ensure include:
-people who watch television and listen to the radio are protected from harmful or offensive material;
-a wide range of high-quality television and radio programmes are provided, appealing to a range of tastes and interests;
-a universal postal service is provided in the UK. This means a six days a week, universally priced delivery and collected service across the UK; and
-television and radio services are provided by a range of different organisations.
OfCom are not responsible for regulating:
-disputes between you and your telecoms provider;
-premium-rate services, including mobile-phone text services and ringtones;
-the content of television and radio adverts;
-complaints about accuracy in BBC programmes;
-the BBC TV licence fee;
-post offices; or
-newspapers and magazines.