In some (maybe most?) cases, you can. Bullies look for easy targets. So all you have to do is decide not to be an easy target and ignore any size difference. I told a story of doing that here, and it did work:
The bully I mentioned above, who took a shotgun to his head? He only stopped bullying me when I threw a basketball into his face (suspension for me, of course). This was after at least a year or 2 of abuse in junior high.
Here's the thing about bullies- the school iteration is only one kind, and you can keep running into them later in life. In all cases you will have to stand up for yourself and fight a bit (perhaps not in actuality, as adults, but it's the same energy source).
I mostly share the story because the idea that you, alone, can stand up to these sorts of situations doesn't seem right to me.