AEI

AEI may refer to:


 * Adelaide Educational Institution of South Australia
 * Aei Latin-script trigraph
 * AEI Music Network Inc. (Audio Environments Incorporated), which created the "Foreground Music" industry in 1971
 * Albert Einstein Institute, the Max Planck Institute for Gravitational Physics, Germany
 * Albert Einstein Institution, an organisation involved in non-violent methods of political resistance based in the US
 * Alliance for European Integration, the ruling coalition in Moldova since the July 2009 election
 * American Enterprise Institute, a conservative think tank
 * Architectural Engineering Institute
 * Archive of European Integration
 * Associated Electrical Industries, large company in the UK (now defunct)
 * Automatic Equipment Identification, as used by the railroad industry
 * Average Earnings Index, British labour market measure
 * Average Earnings Index (horse racing), American horse racing measure
 * Atomic Energy Organization