Nio or NIO may refer to:
Nio (Buddhism), guardians of the Buddha
Nio Inc., a Chinese electric automobile manufacturer
Nicaraguan córdoba, currency by ISO 4217 currency code
National Institute of Oceanography (disambiguation), several organizations
National Institute of Ophthalmology (disambiguation), several organizations
Neurotechnology Industry Organization
Non-blocking I/O (usually "NIO"), a collection of Java programming language APIs introduced with the J2SE 1.4 release of Java by Sun Microsystems
Northern Ireland Office, an arm of the United Kingdom government, responsible for Northern Ireland affairs
Nickel(II) oxide, NiO
Liang (surname), pronounced and romanized as Nio in several southern Chinese variants
