Wikipedia uses sentence case for all article titles and section headings, capitalizing only the first word and proper nouns. This approach prioritizes neutrality and readability over visual emphasis, and it is the editorial standard for the world's largest reference encyclopedia.
Wikipedia style is sentence case applied to article titles and headings: only the first word and any proper nouns are capitalized. All other words, including nouns, verbs, and adjectives that would be capitalized in standard title case, appear in lowercase.
The Wikimedia Foundation mandates this style for all Wikipedia articles to create consistency across millions of pages in hundreds of languages. It also makes titles easier to read and link to within the encyclopedia's internal navigation system.
Wikipedia style applies to Wikipedia itself, as well as other projects in the Wikimedia family, including Wikidata, Wikisource, and Wikinews. Content creators editing Wikipedia are expected to follow this style for all headings and article titles.
Some software documentation projects and technical wikis also adopt sentence case because it matches the natural register of instructional writing. If you are maintaining a wiki or documentation site and want a neutral, readable tone, Wikipedia style is worth considering.
Only the first word of a heading or title is capitalized in Wikipedia style, along with any proper nouns. Proper nouns include names of people, places, organizations, and specific products or brands.
Wikipedia's manual of style is explicit about avoiding title case. The reasoning is that title case is conventional for published works but inappropriate for encyclopedic content that functions more like prose reference than a collection of book titles.
Wikipedia style and sentence case are functionally identical for most practical purposes. Both capitalize only the first word and proper nouns, with no exceptions for other categories of words.
The difference is primarily one of context and authority. Sentence case is a broad grammatical concept, while Wikipedia style refers specifically to the conventions enforced by the Wikipedia editorial community and its automated tools.