Finding the text of a treaty (a.k.a. accord, agreement, convention, etc.) can be easy, but it can also be difficult and time-consuming (even with Google!). Here are two common situations:
For more guidance, read some of the research guides immediately below about treaty research! They are very helpful ...
The titles below will help you to find out where a treaty's text may be found, they do not usually provide the treaty text themselves!
The linked titles below are all available from the vendor HeinOnline. They work best when you are researching a known item -- i.e. you have a full citation for the treaty! (Forget about keyword searching ...)
Here are some sources where keyword searching is actually possible!
Caveat emptor!! I don't think that a comprehensive list exists yet ...