A surgical instrument is a medical device for performing specific actions or carrying out desired effects during a surgery or operation, such as modifying biological tissue, or to provide access for viewing it. Over time, many different kinds of surgical instruments and tools have been invented. Some surgical instruments are designed for general use in all sorts of surgeries, while others are designed for only certain specialties or specific procedures.

A retractor is a surgical instrument used to separate the edges of a surgical incision/wound or to hold away certain organs and tissues so that body parts underneath may be accessed during surgical operations.