仪器飞行（英语：Instrument Flight Rules，IFR）是指以接近完全依赖仪器来导航的飞行方式。

从来的目视飞行是要求飞行员靠地面的地形特征和地标等来驾驶飞机，但是仪器飞行就以地面和机上导航设施协助，计算出路线作飞行。仪器飞行所要用到的地面导航台包括甚高频全向信标和无方向性信标。而区域导航(RNAV)就甚至需要国际民航组织定下的航路(Airway)等。 除了地面仪器外，使用仪器飞行的航空器也必需有相关设备来读取地面导航台的信息和保持飞机在飞行路线内。

Instrument flight rules (IFR) is one of two sets of regulations governing all aspects of civil aviation aircraft operations; the other is visual flight rules (VFR).

FAA's Instrument Flying Handbook defines IFR as: "Rules and regulations established by the FAA to govern flight under conditions in which flight by outside visual reference is not safe. IFR flight depends upon flying by reference to instruments in the flight deck, and navigation is accomplished by reference to electronic signals." It is also a term used by pilots and controllers to indicate the type of flight plan an aircraft is flying, such as an IFR or VFR flight plan.