The stethoscope is an acoustic medical device for listening to internal sounds in the human body. It is most often used to listen to heartbeats and breathing, though it is also used to listen to intestines and to blood flow in arteries and veins.

The stethoscope consists of a contact piece which is placed on the skin of a patient. This contact piece has a membrane, that vibrates to the sounds in the body. This vibration is transmitted through rubber tubes connected to earpieces. Doctors listen to the sounds through the earpieces. There are two types of contact pieces: the first is a bell type of contact which picks up low-pitched sounds while the second is a diaphragm type which picks up high-pitched sounds. Doctors also sometimes use a combination bell-diaphragm contact piece.

The stethoscope is used in aid of diagnosing certain diseases. The stethoscope is able to transmit certain sounds and exclude others. Listening this way is known as auscultation. Before the stethoscope was invented, doctors placed their ear next to the patient's body.

The stethoscope was invented in France in 1816 by René-Théophile-Hyacinthe Laennec. It consisted of a hollow wooden tube.

Stethoscopes are often considered as a symbol of the doctor's profession, as doctors are often seen or depicted with a stethoscope hanging around their neck.