Stadia may refer to:
- One of the plurals of stadium; "stadiums" is also used.
- Stadia (length), an ancient unit of distance
- Stadia mark, marks on a telescopic sight's reticle that permit stadiametric rangefinding or altitued measurements (height finding)
- Stadia rod, a related surveying tool used with telescopic based survey instruments
- Stadiametric rangefinding, a way of measuring distance using a telescope and triangulation
- Helsinki Polytechnic Stadia, a multidisciplinary institution of higher education in Finland