Rhenium (Re) is a metallic chemical element with atomic number 75. There are two naturally occurring rhenium isotopes, the stable ¹⁸⁵Re and the radioactive ¹⁸⁷Re.

Rhenium is a very rare element, found in the Earth's crust at a concentration of about 1 microgram per kilogram, i.e. 1 ppb (part per billion).

Rhenium has an extremely high melting point and boiling point, and its major industrial use is in alloys where heat resistance is crucial, such as in jet engine components.