Advertising mail, also known as direct mail, junk mail, or admail, is the delivery of advertising material to recipients of postal mail. The delivery of advertising mail forms a large and growing service for many postal services, and direct-mail marketing forms a significant portion of the direct marketing industry. Some organizations attempt to help people opt out of receiving advertising mail, in many cases motivated by a concern over its negative environmental impact.

Advertising mail includes advertising circulars, coupon envelopes, catalogs, CDs, “pre-approved” credit card applications, and other commercial merchandising materials delivered to homes and businesses. It may be addressed to pre-selected individuals, or unaddressed and delivered on a neighbourhood-by-neighbourhood basis.

Postal systems offer lower rates for buyers of bulk mail permits. In order to qualify for these rates, marketers must format and sort the mail in specific ways – which reduces the handling required by the postal service.