CIE may refer to:

• Cambridge International Examinations, an international examination board
• Center for International Education at the University of Massachusetts-Amherst
• Cleveland Institute of Electronics, a private technical and engineering educational institution
• , the International Commission on Illumination
• , the national electrical company in Ivory Coast
• Companion of the Order of the Indian Empire (C.I.E.)
• Computability in Europe, an international organization of computability theorists, computer scientists, mathematicians
• Córas Iompair Éireann, the Irish state transport authority
• Council on Islamic Education
• Transportes Aéreos Cielos Andinos, ICAO code: "CIE"
• Computing Interfacing and Engineering, Consulting firm in Melbourne Victoria

Córas Iompair Éireann (, Irish Transport System), or CIÉ, is a statutory corporation of the Republic of Ireland, answerable to the Irish Government and responsible for most public transport in the Republic of Ireland and – jointly with its Northern Ireland counterpart, the Northern Ireland Transport Holding Company – the railway service between the Republic and Northern Ireland.

Cambridge International Examinations (CIE) are a provider of international qualifications, offering examinations and qualifications in more than 160 countries. Qualifications offered by CIE include: Cambridge International General Certificate of Education - Advanced Level (Cambridge International GCE A-Levels), the AICE Diploma (Advanced International Certificate of Education Diploma), the Cambridge Pre-U programme, IGCSEs and Key Stage examinations for primary and secondary schools across the globe. The examination board is a division of Cambridge Assessment, founded as a department of the University of Cambridge in 1858. CIE offer examinations and qualifications, which are open to students at registered CIE centers