HIO may refer to:
- Hillsboro Airport, in Washington County, Oregon, United States
- Hypoiodous acid, an oxidising agent
- Hybrid input-output algorithm, in coherent diffraction imaging
- Oslo University College, the largest state university college in Norway
- Østfold University College, a further and higher education institution in south-eastern Norway
- Tsoa language, spoken in Botswana and Zimbabwe
This disambiguation page lists articles associated with the title HIO.If an internal link led you here, you may wish to change the link to point directly to the intended article. Category: