ESN

ESN may refer to:


 * Eastern Security Network, the armed wing of the Indigenous People of Biafra (IPOB)
 * Easton Airport (Maryland), United States
 * Echo state network in computer science
 * Edmonton Street News, a Canadian newspaper
 * Einstein summation notation, used in mathematical physics
 * Electronic serial number for mobile devices
 * Emergency Services Network, in the UK
 * Enterprise Social Network
 * Entertainment Studios Networks, an American cable network
 * Erasmus Student Network, a European student organization
 * Europe of Sovereign Nations, a far-right political group in the European Parliament
 * European Sensory Network, studies the five senses
 * European Society for Neurochemistry
 * Salvadoran Sign Language