ISP often refers to Internet service provider. ISP may also refer to:

• Islip railway station (Network Rail station code ISP), England
• Long Island MacArthur Airport (IATA Airport code ISP), New York, US

• Information Society Project, at Yale Law School
• Institute of Southern Punjab, a university in Pakistan
• Instituto Superior Politécnico, a university in São Tomé and Príncipe
• Institut supérieur de philosophie, the Higher Institute of Philosophy in Louvain-la-Neuve, Belgium
• Integrated science program, an honors program at Northwestern University
• International School of Panama
• International School of Paris, France
• International School of Prague, Czech Republic
• Petnica Science Center (Istraživačka Stanica Petnica)

• Idaho State Police
• Illinois State Police
• Indiana State Police
• Iowa State Patrol
• Iowa State Penitentiary, Fort Madison, Iowa, US

• Illinois State Police
• Indiana State Police
• Independence for Scotland Party
• Independent Socialist Party (disambiguation), in several countries
• ISP Sports, US marketing and broadcast company
• National Inspectorate of Strategic Products (Sweden) (Swedish: Inspektionen för strategiska produkter)
• Integrated Service Provider, a type of logistics services firm
• Intesa Sanpaolo, Italian bank
• Sovereign and Popular Italy (Italia Sovrana e Popolare), Italian political party

• Image signal processor
• In-system programming, of programmable logic devices in-circuit
• Information Systems Professional, an information technology title and post-nominal
• Interface segregation principle, a principle of object-oriented design
• Internet service provider, an organization that provides services for accessing, using, or participating in the Internet
• ISP Formal Verification Tool, a verification tool for MPI (Message Passing Interface) programs

• Imperial smelting process, in zinc smelting
• Polarization in astronomy, interstellar polarization
• Specific impulse (I_sp), a measure of rocket and jet efficiency