Atrium may refer to:

  • Atrium (architecture), a large open space within a building usually with a glass roof
  • Atrium (alveoli), microscopic air sacs in lungs
  • Atrium (heart), an anatomical structure of the heart
  • Atrium of the ventricular system of the brain
  • Atrium (Cardiff), a University of Glamorgan (Wales) building in Cardiff
  • Atrium, the genital structure next to the genital aperture in the reproductive system of gastropods
  • Atrium, an alternative rock band.