A safety pin is a variation of the regular pin which includes a simple spring mechanism and a clasp. The clasp serves two purposes: to form a closed loop thereby properly fastening the pin to whatever it is applied to, and to cover the end of the pin to protect the user from the sharp point.

Safety pins are commonly used to fasten pieces of fabric or clothing together. They are widely used to fasten cloth diapers (nappies), as the safety clasp prevents the baby from being jabbed. Similarly, they can be used to patch torn or damaged clothing. Safety pins can also be used as an accessory or jewelry, such as earrings, chains, and wristbands. Sometimes they are used to attach an embroidered patch.

The fibula, a form of a brooch, was invented by the Myceaneans on the Greek Peloponnesus between the 13th and 14 BC, and is considered an early precursor to a safety pin since they were used in a similar manner. However, it had major flaws. It had no clasp or spring at the end to help put it in place. Over the centuries, the fibula became forgotten.