A revenue stamp, or fiscal stamp is a type of adhesive label used to collect taxes or fees on various items. Many countries of the world have used them, for documents, tobacco products, liquor, drugs, playing cards, and other kinds of things. While revenue stamps resemble postage stamps, they are not found on mail, nor do they (usually) receive a cancellation.

The use of revenue stamps goes back further than that of postage stamps; the stamps of the Stamp Act of the 18th century were revenues. Their use became widespread in the 19th century, partly inspired by the success of the postage stamp, and partly motivated by the desire to streamline government operations, the presence of a revenue stamp being an indication that the item in question had already paid the necessary fees. Revenue stamps have become less commonly seen in the 21st century, with the rise of computerization and the ability to use numbers to track payments accurately.

There are a great many kinds of revenue stamps in the world, and it is likely that some are still uncataloged. Both national and subnational entities have issued them. While some use a single design for all forms of fee payment, others have introduced distinct designs usable for only a single type of item. In certain periods government have combined the uses of postage and revenue stamps, calling them "postal fiscals" or inscribing them "Postage and Revenue".