Stamp collecting is the collecting of postage stamps and related objects. It is an area of philately, which is the study of stamps. It has been one of the world's most popular hobbies since the late nineteenth century with the rapid growth of the postal service, as a stream of new stamps was produced by countries that sought to advertise their distinctiveness through their stamps.

A postage stamp is a small piece of paper issued by a post office, postal administration, or other authorized vendors to customers who pay postage. Then the stamp is affixed to the face or address-side of any item of mail—an envelope or other postal cover —which they wish to send. The item is then processed by the postal system, where a postmark or cancellation mark—in modern usage indicating date and point of origin of mailing—is applied to the stamp and its left and right sides to prevent its reuse. Next the item is delivered to its addressee.