An intermediate-range ballistic missile (IRBM) is a ballistic missile with a range of 3,000–5,500 km, between a medium-range ballistic missile (MRBM) and an intercontinental ballistic missile (ICBM). Classifying ballistic missiles by range is done mostly for convenience. In principle there is very little difference between a low-performance ICBM and a high-performance IRBM, because decreasing payload mass can increase the range over the ICBM threshold. The range definition used here is used within the U.S. Missile Defense Agency.

The Aggregat series was a set of ballistic missile designs developed in 1933–1945 by a research program of Nazi Germany's Army (Heer). Its greatest success was the A4, more commonly known as the V2.