If you mean a straight boarding school, I doubt they would work. I know some will accept a child with special needs, but not many and the odds are pretty good that you're looking at a quick and very expensive expulsion. In the past, people sent their ODD-type kids to military schools. Some had success, most did not.
The best type of school to look at are emotional growth boarding schools. They are more expensive but they are designed for kids with emotional problems. You'd have to do some serious research to see if it is a good fit. Talk to parents who have kids there now, kids who have graduated, kids who dropped out. See if any professionals in your area have heard of the school and would recommend them. If you find the right school for your child, I think you have a good chance at success if there aren't other issues that need to be resolved (and ODD rarely stands alone!).
We're thinking about it but it would have to be a school specially geared toward ADHD, etc. The psychiatric told us that military schools won't accept kids with-our son's diagnosis.
We know two people who sent their sons to local boarding schools for "normal" behavior problems (out of control brats who wouldn't listen, but no ADHD and no psychiatric diagnosis) and both were very successful. Within 2 mo's they were getting straight A's and winning awards. One came home at the end of the school yr, and the other one will finish HS at the boarding school.