In marketing, scarcity or the scarcity principle is used for creating a sense of urgency and persuading customers to buy something before the offer runs out. Scarcity can be applied to any industry, and refers to any limitation that can be placed on a product or service, for increasing sales: limited quantity, time-based deadline, reduced the price if acting quickly, bonus item for immediate purchase and so on.

Scarcity marketing is used both online and offline and requires fewer resources than other strategies used for encouraging sales, such as offering free gifts, organizing contests or giveaways, or collecting reviews and testimonials to be used as social proof.