A reseller is a company or individual (merchant) that purchases goods or services with the intention of selling them rather than consuming or using them. Individual resellers are often referred to as middle men. This is usually done for profit (but can be done at a loss). One example can be found in the industry of telecommunications, where companies buy excess amounts of transmission capacity or call time from other carriers and resell it to smaller carriers. Resale can be seen in everyday life from yard sales to selling used cars.

According to the Institute for Partner Education & Development, a reseller's product fulfillment–based business model includes a corporate reseller, retail seller, direct market reseller (DMR), and an internet retailer (eTailer); less than 10 percent of its revenue comes from services.