For software, see Wikipedia:Software (WP:SOFT); for Spoken Wikipedia, see Wikipedia:WikiProject Spoken Wikipedia (WP:WSW). For Wikipedia guidelines regarding non-spoiler warnings, see Wikipedia:No disclaimer templates (WP:NDT).

A spoiler is a piece of information in an article about a narrative work (such as a book, feature film, television show or video game) that reveals plot events or twists.

Spoiler (media) discusses spoiler warnings: "The term spoiler is associated with specialist Internet sites and in newsgroup postings." The idea was not to spoil people's enjoyment of a current fictional work (usually a film or book) by discussing it before other readers would have had a chance to see or read it themselves.

Because some people prefer to avoid spoilers, it became common on the Internet to put before such descriptions a spoiler warning. In scholarly reference works, however, this is rare, and thus spoiler warnings are generally avoided on Wikipedia.

In deciding the structure, content or formatting of an article, spoilers should be given low weight. If a piece of information that could be considered a spoiler is one of the most essential aspects of a topic it should be present in the article lead. However dramatic a plot-twist may be in the context of the fictional world, it is probably a fairly standard authorial maneuver from the real-world perspective that should be used in Wikipedia.

Decisions about what content is essential in the lead or in the body of the article is always at the discretion of the editor. Nothing in Wikipedia policy or the Manual of Style mandates that plot summaries should be so detailed that spoilers must inevitably be included.

In cases where plot details genuinely are not widely known (i.e. not discussed in secondary sources but only in the primary source, i.e. the fictional work itself) care must be taken not to violate Wikipedia's policies on original research.

• Spoiler warnings must not interfere with neutral point of view, completeness, encyclopedic tone, or other elements of article quality.
• Spoiler warnings are never appropriate for ancient texts, literary classics, classic films, or works whose plot is 'common knowledge'. In grey areas, editors placing spoiler templates should attempt to justify this on the individual article's talk page, and should expect vigourous discussion.
• Spoiler warnings must never be used for non-fictional subjects. If explicit spoilers^[1] are mentioned in articles on primarily non-fictional subjects (e.g. authors, real-life places that fictional texts are set, literary concepts like twist ending), editors should consider whether such mentions are really necessary.
• Spoiler tags are redundant when used in ==Plot== or other sections that are clearly going to discuss the plot. Using such headers is stylistically preferable to a tag.
• Articles about fictional characters, objects or places can be expected to be substantially made up of elements of the story in question and should not need spoiler warnings.

• Spoiler warnings may be used in articles whose primary subject is fictional where the editors proposing them can provide a compelling and justifiable reason to insert one. Such reasons should show that knowledge of the spoiler would likely substantially diminish many readers' enjoyment of the work.
• A spoiler warning is a courtesy note to readers, such as those who find articles from search engine results. As such it's more of a reminder note and not a label to be used for every plot summary—only those which contain serious spoilers, and even then at the discretion of the consensus of editors for each article. Such a note is never guaranteed.
• A spoiler about a fictional work should not be needed in an article whose primary subject is not that work — particularly if the spoiler is added as a piece of trivia, or as an example when a non-spoiler example would do just as well. For instance one might reasonably, if consensus for this exists, remove information about a plot twist in a film about ghosts from the article Ghost, but not from the article about that film. Such a deletion is worth considering if inclusion of the spoiler (in a largely unrelated article) makes a disruptive warning seem appropriate.
• Use only {{Spoiler}} to mark spoilers.

The following methods should never be used to obscure spoilers:

• Deleting relevant, neutral and verifiable information about a narrative work from a Wikipedia article about that work "because it's a spoiler".
• Making "spoiler free" parallel versions (content forks) of an article about a fictional work. (Since Wikipedia content is available under the text of the GNU Free Documentation License, creating parallel versions outside of Wikipedia is generally acceptable.)
• Structuring an article around spoilers, confining them to a particular area of the article (e.g. under ==Plot==), when unnecessary or in a way that decreases article quality.
• In various Internet discussion forums, a widespread convention is the insertion of blank (or virtually blank) lines before a spoiler (which removes the offending text from the reader's view, until he/she scrolls to the next page). Obviously, this is unacceptable in a general-purpose encyclopedia.
• On the Usenet computer network, a popular method of concealing spoilers (and sometimes, offensive material) is ROT13 encryption. Again, this is unacceptable in a general-purpose encyclopedia.
• Another common method of hiding spoilers from readers is to change the color of the text to match that of the page background, thus rendering the text unreadable until highlighted by the reader in a selection. Hiding text in this manner is unacceptable here because it requires explanation to readers unfamiliar with the practice, and because it may be incompatible with computer accessibility devices such as screen readers. Also, some web browsers highlight text by inverting the colors of the text and background. In these browsers, for white text on a white background, highlighting produces black text on a black background. Also, it is possible for a user to set their browser to refuse to change text color (just as they can refuse to display images); text-only browsers (such as Lynx) may likewise disregard requests to change text color. In addition, it renders the text unprintable.

The use of spoiler warnings is controversial amongst Wikipedians. Key arguments against are:

• As Wikipedia is an encyclopedia, rather than a current event discussion forum, it should be assumed that it will contain information — in fact, it is stated explicitly in the general content disclaimer that "WIKIPEDIA CONTAINS SPOILERS AND CONTENT YOU MAY FIND OBJECTIONABLE".
• To warn about such content is redundant, since they usually occur in sections marked "Plot", "Plot Summary", or "synopsis".
• Such warnings are disproportionate — as a matter of policy (Wikipedia:No disclaimer templates) we don't warn about other objectionable content, including, in cases such as Jyllands-Posten Muhammad cartoons controversy, content that people have been killed over.
• In six years, there are zero documented reader (as opposed to editor) complaints about a lack of spoilers in Wikipedia, when readers complain at length about every other aspect of Wikipedia's content.

Counter-arguments are:

• Few readers look at disclaimer pages. Much traffic to the relevant articles comes directly from search engines, bypassing Wikipedia's front matter.
• The text will frequently be present on mirror sites where our disclaimer is absent.

Some Wikipedias forbid spoiler warnings entirely, like the German Wikipedia (de:Wikipedia:Spoilerwarnung). A similar route has been taken by some individual WikiProjects on the English Wikipedia, such as WikiProject Final Fantasy and WikiProject Opera.