The initialism IES may refer to:
Government organizations Indian Economic Service Indian Education Service, in British India Institute for Environment and Sustainability of the European Commission Institute of Education Sciences of the U.S. Department of Education
Non-profit organizations Institute for the International Education of Students Illuminating Engineering Society International Enterprise Singapore International Society of Endocrinology Israel Endocrine Society Israel Exploration Society Institution of Environmental Sciences
Companies IES Ltd (Integrated Export Systems), a transportation software company Integrated Electrical Services Internationella Engelska Skolan
Other Indian Engineering Services The Indrema Entertainment System, also known as the L600, an unreleased sixth generation video game console Integrated Encryption Scheme, in cryptography, a public key cryptosystem Intertemporal elasticity of substitution Intuitive eating scale