Depending on your employer there are a variety of options.
Firstly - you can just contact your employer, and have them send you another copy. They are required to have a copy of your W2 on file for their own tax purposes I would imagine, so it might be just as simple as going in and having them copy it for you.
Secondly - more and more businesses are going paperless. If your company uses an internet, or some kind of web platform to enter your time each day/week - chances are you can probably get a copy of your W2 by utilizing that web platform and looking at your pay statement section.
Hope this helps!