A trocar is a surgical instrument with a sharp tip used to create a hole in the body that can be used to introduce a surgical instrument. A trocar is most often attached to a tube called a cannula, along which surgical instruments are passed through the trocar and into the body. Trocars are widely used in laparoscopic surgery. They are also used by the funeral industry during embalming.

Although trocars are traditionally sharp, the blades can come in different styles, from the classic three-pronged blade on traditional trocars to the dull blade on the bladeless version of the instrument. The trocar can also be shielded, and a small shield snaps into place to prevent damage to the patient's internal organs after the trocar is inserted. These devices are typically designed for single use, with the trocar discarded after use by one patient.