| name = Io
| alt_names =
| adjectives =
| image = Io highest resolution true color.jpg
| image_alt = True-color image taken by the ''Galileo'' orbiter
| caption = ''[[Galileo (spacecraft)|Galileo]]'' spacecraft true-color image of Io. The dark spot just left of the center is the erupting volcano [[Prometheus (volcano)|Prometheus]]. The whitish plains on either side of it are coated with volcanically deposited [[sulfur dioxide]] frost, whereas the yellower regions contain a higher proportion of [[sulfur]].
| bgcolour = #a0ffa0
| discoverer = [[Galileo Galilei]]