Europium (Eu) is a chemical element with atomic number 63. Out of all elements in the lanthanide series, europium is the most reactive.

There are two naturally occurring europium isotopes, the radioactive¹⁵¹Eu and the stable ¹⁵³Eu.

There aren't that many industrial uses of europium, but europium oxide (Eu₂O₃) is sometimes used as the red color component in TVs and lamps.