From their page about username policies:

Wikipedia usernames are case sensitive, but the first letter is always automatically capitalized.

But I've also noticed that, even though I always login by typing "matt" (not actually my username, of course), I can still login, even though they change it to "Matt". So is it really case-sensitive? And why do they do this? I've never seen any other site capitalize the first letter of a username before.

3 Answers 3


Usernames are a subset of page titles, and must follow the rules for page titles. Mediawiki, the software behind Wikipedia, treats by default all article titles as beginning with a capital letter (unless the first character is not a letter).

Note that $wgCapitalLinks can be used to disable auto-capitalization for page titles. According to this discussion, usernames are always capitalized for compatibility though. (might have changed since then?)

  • 2
    You're mostly right, but this is just the default. For example Woktionary page names are fully case sensitive.
    – svick
    Dec 8, 2013 at 3:20

It's a technical restriction with the MediaWiki software. All page names and page titles must begin with a capital letter.

Technical restrictions and limitations

[...] These limitations and restrictions include:

  • A pagename can not begin with a lowercase letter (in any alphabet).

Since user pages are subsets of normal pages, they are also affected by this limitation.

When you see a page title, or user page title, with a lower case first letter, they are using the {{lowercase title}} template to force the style.


The first letter of the username on Wikipedia is not case sensitive and is forced upper-case. However, including the code

{{lowercase title}}

at the top of your user page and talk page displays your username in lowercase.

Also remember to customize your signature on Special:Preferences, for example:

[[User:Justinacolmena|justinacolmena]] ([[User talk:Justinacolmena|talk]])

so that your username is also displayed in all lowercase.

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