The Northern Ireland Office (or NIO; is a department of HM Government of the United Kingdom, responsible for Northern Ireland affairs. The NIO is led by the Secretary of State for Northern Ireland, currently Shaun Woodward MP supported by Paul Goggins MP. The NIO, based at Stormont, has responsibility for the areas which have not been devolved to the direction and control of the Northern Ireland Assembly. These include law and order, political affairs, policing and criminal justice.

If devolution is suspended then the rule of Northern Ireland through the NIO in lieu of the Northern Ireland Executive is referred to as direct rule.