ECI may refer to:
Companies ECI Partners, a British private equity group ECI Telecom, an Israeli telecommunication equipment manufacturer Egg Clearinghouse, an American egg clearinghouse El Corte Inglés, a Spanish retailer Engine Components Inc., an American aircraft engine manufacturer Eze Castle Integration, a managed services provider for financial services firms
Education Early childhood intervention, a support and educational system for very young children Eastwood Collegiate Institute, in Kitchener, Ontario, Canada Emergency care instructor, a person who provides training in emergency care Etobicoke Collegiate Institute, in Ontario, Canada
Government bodies Election Commission of India, a body established by the Constitution of India European Citizens' Initiative, in the European Union Evangelical Climate Initiative, in the United States
Indexes Economic Complexity Index, an economic indicator Efficiency of conversion, efficiency of food conversion, an index measure of food fuel efficiency in animals Employment cost index, in the United States
Science and technology Earth-centered inertial, a coordinate system Enhanced Cartridge Interface, a computer interface Enterprise content integration, a software technology Extended Channel Interpretation, a communication protocol extension for the bar code reader to host interface European Color Initiative, an expert group E-UTRAN Cell Identity (ECI), an identity for a cell within a network in LTE
Other uses Eastern Congo Initiative, an American development charity Engineering Council of India Evangelical Church of India World Federation of Energy, Chemical and Various Industry Workers' Unions, a former international trade union secretariat