Ems or EMS may refer to:

Places and rivers
Domat/Ems, a Swiss municipality in the canton of Grisons
Ems (river) (Eems), a river in northwestern Germany and northeastern Netherlands that discharges in the Dollart Bay
Ems (Eder), a river of Hesse, Germany, a tributary of the Eder
River Ems (Chichester Harbour), an English river with its mouth at Emsworth, Hampshire
Bad Ems, a German town in Rhineland-Palatinate, until 1913 named Ems

Businesses
Eastern Mountain Sports, an outdoor retailer
Eitzen Maritime Services, a Norwegian company
Electronic Music Studios, a manufacturer of synthesizers
Elektromreža Srbije, a Serbian electric utility company
Event Marketing Solutions, a UK-based provider of vehicle-based marketing roadshows
Ems-Chemie, Swiss chemical company
EMS (pharmaceuticals), a Brazilian pharmaceutical company
EMS Technologies, an American company

Organizations
Edinburgh Mathematical Society
Environmental Media Services, an American nonprofit organization
European Monetary System, a former European monetary cooperation
European Mathematical Society

Schools
United States
Eagleview Middle School, El Paso County, Colorado
Eastern Middle School, Montgomery County, Maryland
Elwood Middle School, New York
Penn State College of Earth and Mineral Sciences (commonly referred to as EMS), part of Penn State University, University Park, Pennsylvania
Eastern Mennonite School, Harrisonburg, Virginia
Eastern Mennonite Seminary, Harrisonburg, Virginia

Elsewhere
Earl Marriott Secondary School, Surrey, British Columbia, Canada
English Martyrs School and Sixth Form College, Hartlepool, County Durham, England
Exeter Mathematics School, Exeter, Devon, England
EM Strasbourg Business School, Strasbourg, France

Science and technology
Physics, chemistry, and biology
Electromagnetic suspension, a method to suspend an object
Electromagnetic spectrum, is the range of all possible electromagnetic radiation
Ethyl methanesulfonate (or methanesulfonic acid ethyl ester), a mutagen
European macroseismic scale, a scale used when measuring earthquakes intensity
Environmental Mutagen Society

Computer and engineering
Electronics manufacturing services, a type of company
Electronic meeting system, a collaborative computer software
Element management system, software to monitor and control network elements (devices) in telecommunications
Emergency Management Services, a part of MS-Windows
Energy management software, software to monitor and optimize energy consumption in buildings or communities
Energy management system, a system to control, monitor, and optimize the generation and flow of Electric Power
Engine management system, see engine control unit
Enhanced Messaging Service, an extension to Short Message Service (SMS) for mobile phone
Expanded Memory Specification, a memory specification for x86 PCs supported by DOS etc.
Enterprise messaging system, a middleware system for sending messages between two or more clients
Execution management system, a trading system with a user interface for market data, indicators and order entry

Medical and veterinary
Emergency medical services, a service providing out-of-hospital acute care and transport
Eosinophilia–myalgia syndrome, a neurological condition
Electrical muscle stimulation, a type of medical therapy, also referred to as Electro Myo-Stimulation, a technique used in sports training and rehabilitation
Equine metabolic syndrome, a horse disease

Other science and technology
Earthen manure storage, structures for the storage of liquid livestock manure
Environmental management system, part of a management system of an organization similar to a quality management system
Engine monitoring system, data logging, display and alerting device, a simpler form of an aircraft engine-indicating and crew-alerting system
Expected mean squares, in statistics

Other uses
Ems (ship), an 1893 British iron sailing ship
Express Mail Service, an international express postal service offered by members of the Universal Postal Union
Experimental Music Studios, computer music center at the University of Illinois
E. M. S. Namboodiripad (1909–1998), Indian communist leader
Expeditionary Medical Ship (U.S. Navy)

See also
Ems Dispatch, a historical document
EM (disambiguation)