ISAR may refer to:

• Intergovernmental Working Group of Experts on International Standards of Accounting and Reporting (ISAR)
• International Search and Rescue Competition
• Institute for the Study of Academic Racism
• Inverse synthetic aperture radar, a technique to generate two-dimensional radar images of a target
• Intelligible semi-automated reasoning, declarative mode proofs for Isabelle (theorem prover)

The Isar is a river in Tyrol, Austria and Bavaria, Germany. Its source is in the Karwendel range of the Alps in Tyrol; it enters Germany near Mittenwald, and flows through Bad Tölz, Munich, and Landshut before reaching the Danube near Deggendorf. At in length, it is the fourth largest river in Bavaria, after the Danube, Inn, and Main. It is Germany's second most important tributary of the Danube after the Inn.

ISAR may refer to:

• Intergovernmental Working Group of Experts on International Standards of Accounting and Reporting (ISAR)
• International Search and Rescue Competition
• Institute for the Study of Academic Racism
• Inverse synthetic aperture radar, a technique to generate two-dimensional radar images of a target
• Intelligible semi-automated reasoning, declarative mode proofs for Isabelle (theorem prover)

The Isar is a river in Tyrol, Austria and Bavaria, Germany. Its source is in the Karwendel range of the Alps in Tyrol; it enters Germany near Mittenwald, and flows through Bad Tölz, Munich, and Landshut before reaching the Danube near Deggendorf. At in length, it is the fourth largest river in Bavaria, after the Danube, Inn, and Main. It is Germany's second most important tributary of the Danube after the Inn.