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
• Educationally subnormal, term for special-needs students
• 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