Newsgroup spam is a type of spam where the target of the spamming are Usenet newsgroups.

Spamming of Usenet newsgroups actually pre-dates email spam. The first widely recognized Usenet spam was an advertisement for legal services. It was posted in April 1994 by lawyers Laurence Canter and Martha Siegel, and hawked legal representation for United States immigrants seeking papers ("green cards").

Old Usenet convention defines spamming as excessive multiple posting, that is, the repeated posting of a message (or substantially similar messages). During the early 1990s there was substantial controversy among Usenet system administrators (news admins) over the use of cancel messages to control spam. A cancel message is a directive to news servers to delete a posting, causing it to be inaccessible to those who might read it. Some regarded this as a bad precedent, leaning towards censorship, while others considered it a proper use of the available tools to control the growing spam problem.

Throughout that period, the term "spam" on Usenet was used to refer specifically to excessive multiple posting. Other terms were coined for similar behaviors such as excessive cross-posting or the posting of individual off-topic advertisements.

See also: sporgery