Emergency medical services (EMS), also known as ambulance services or paramedic services, are emergency services that provide urgent pre-hospital treatment and stabilisation for serious illness and injuries and transport to definitive care. They may also be known as a first aid squad, FAST squad,emergency squad,ambulance squad, ambulance corps,life squad or by other initialisms such as EMAS or EMARS.

In most places, the EMS can be summoned by members of the public (as well as medical facilities, other emergency services, businesses and authorities) via an emergency telephone number which puts them in contact with a control facility, which will then dispatch a suitable resource for the situation. Ambulances are the primary vehicles for delivering EMS, though some also use cars, motorcycles, aircraft, or boats. EMS agencies may also operate a non-emergency patient transport service, and some have rescue squads to provide technical rescue services.

As a first resort, the EMS provide treatment on the scene to those in need of urgent medical care. If it is deemed necessary, they are tasked with transferring the patient to the next point of care. This is most likely an emergency department of a hospital. Historically, ambulances only transported patients to care, and this remains the case in parts of the developing world. The term “emergency medical service” was popularised when these services began to emphasise diagnosis and treatment at the scene. In some countries, a substantial portion of EMS calls do not result in a patient being taken to hospital.