A newsletter is a printed or electronic report containing news concerning the activities of a business or an organization that is sent to its members, customers, employees or other subscribers. Newsletters generally contain one main topic of interest to its recipients. A newsletter may be considered grey literature.

E-newsletters are delivered electronically via e-mail and can be viewed as spamming if e-mail marketing is sent unsolicited.

The newsletter is the most common form of serial publication. About two thirds of newsletters are internal publications, aimed towards employees and volunteers, while about one third are external publications, aimed towards advocacy or special interest groups

Newsletter marketing is a form of direct-to-consumer advertising. This is used by companies that want to send information directly to potential and existing customers. When received unsolicited, they can be seen as spam.

Newsletters are also used by organizations to inform their members of ongoing developments