Guild Wars 2

Wiki page

http://wiki.guildwars2.com/wiki/Squad

Doesn’t have any information on how to leave a squad by yourself, only how to join it.

Chat command:
/squadleave

You can leave a squad the same way you join. In addition to the chat command:

-open map and right click on commander tag and leave squad
-open party interface on top left and click leave squad.