Oh yes. Curriculum can vary wildly. I had a co-worker who moved here (Texas) from California a few years back. He's got 4 kids who, at the time, ranged from like 3rd grade through 10th. They were all nearly made to repeat the same grade they had just finished in CA, because they didn't meet the TX standards. He paid for tutoring for all of them to get them up to TX's idea of grade level.
And when I moved to TX from MD after 10th grade, I only ended up needing like 8 classes to graduate down here, because my education in MD was quite a bit ahead of what they were doing down here.
