Niobium (Nb) is a chemical element with atomic number 41. There is only one stable niobium isotope, ⁹³Nb, with 41 protons and 52 neutrons.

Most niobium is used in steel alloys, but another notable use of niobium is in superconducting magnets, which are for example used in particle accelerators.

Niobium was originally called colombium, but the IUPAC standardized name, since the 1950s, is niobium.