Cio

CIO may refer to:

Organizations

Central Imagery Office, an office of the US Department of Defense that was a predecessor of the National Geospatial-Intelligence Agency
Central Intelligence Office, the national intelligence agency of the former South Vietnam
Central Intelligence Organisation, the national intelligence agency of Zimbabwe
Corruption Investigation Office for High-ranking Officials, a government agency of South Korea

Centro de Investigaciones en Optica, a Mexican research centre in optics
Charitable incorporated organisation, a form of legal entity for non-profit organizations in the United Kingdom
Comité international olympique or International Olympic Committee, an international sports federation
Congress of Industrial Organizations or Committee of Industrial Organization, a 1935–1955 national trade union centre that merged into the AFL-CIO
Credit and Investments Ombudsman, an Australian dispute resolution service

Chairperson-in-office, an official of a member state holding the presidency of an international organization
- Commonwealth Chairperson-in-Office, an official of the Commonwealth of Nations
Chief information officer, the head of information technology
Chief innovation officer, the head of innovation, responsible for innovation management
Chief investment officer, the head of investments

CIO (magazine), both print and online
Concurrent input/output, a feature in the JFS file system
Conventional International Origin, a conventionally defined reference axis of the pole's average location
"Cry it out", an aspect of the Ferber method for solving childhood sleep problems
City One station, Hong Kong, MTR station code