Manual:$wgDefaultSkin

Skins: $wgDefaultSkin
The default skin for new users.
Introduced in version:	1.3.0
Removed in version:	still in use
Allowed values:	(string)
Default value:	'vector' 'monobook' in 1.3.0–1.17.0

Other settings: Alphabetical | By Function

Details

This setting defines the default skin and should be set to the lowercase name of the skin (e.g. 'monobook', not 'MonoBook').

Note that this only sets the default skin, for new users and anonymous visitors. Registered users may change this to any one of the other available skins through their preferences page (see Manual:$wgSkipSkin/Manual:$wgSkipSkins on how to control that).

Note also that upon registration the value of $wgDefaultSkin is copied to the user preferences; thus setting it to another skin it won't have any effect on registered users, even if they never changed their preferences. See Manual:UserOptions.php for how to change that.

Available skins

This is a full list of the skins that have been available within MediaWiki (without the use of additional skin extensions). The version column has not yet been filled in, but this information needs to be added to the page, as not all these skins were introduced at the same time, and some of them are no longer available in a standard installation.

The first column gives the ID which should be used to configure this setting, the second gives the name as it appears within the MediaWiki interface and the third indicates the versions of MediaWiki that this skin is available for:

ID	Name	Versions
standard	Classic	pre-1.0 – 1.21
nostalgia	Nostalgia	pre-1.0 – 1.21
cologneblue	Cologne Blue	pre-1.0 – ??
davinci	DaVinci	(removed in 1.4)
modern	Modern	1.12+
mono	Mono	??
monobook	MonoBook	1.3+
myskin	MySkin	?? – 1.21
chick	Chick	?? – 1.21
simple	Simple	?? – 1.21
vector	Vector	1.16+

An alternative way of checking which of the above skins are available in your particular version of MediaWiki is to check languages/Language.php.