Which License is DokuWiki Under?

I'm a little bit confused about the license of DokuWiki. Can I use it on a commercial website?

The short answer is yes.

The one that is probably the one you are interested in, is the one for the software. It's the GNU General Public License (or shorter: GPL). This means (simply spoken):

You get some rights:

1. You get the software and the sourcecode
2. You are allowed to use the software in any way you like
3. You are allowed to change the sources to your needs

But you have to accept these terms:

1. There are no guarantees of any kind - if it breaks anything for you then it's your problem ¹⁾
2. If you want to redistribute the software you need to do this under the terms of the GPL, which means you have to redistribute the full sourcecode (including your modifications) too.
3. You may not redistribute the software and say you wrote it all yourself - but that is pretty obvious anyway isn't it?

The second license applies to all the content which is created at dokuwiki.org. It is licensed under the Creative Commons Attribution - ShareAlike license (abbreviation: CC-BY-SA).

See the FAQ on the Licenses.