Yes and no. It depends on what you are studying and how the program is set up. Does the class emphasize problem solving skills and ingenuity or route memorization and hard work?

Also, juggling multiple classes requires study skills, organization skills, etc. that are not part of intelligence.

But being very intelligent can help you get by in high school or university if you are lacking in focus, study skills, organization skills, and discipline. For example, if you very intelligent, generally you may only need to read something once to understand it, whereas someone else may need to read it multiple times and ask a bunch of questions. So naturally the second person will require better study skills and planning to pass the course.

My adhd wasn't diagnosed until I was 14, and I truly believe the only way I made it through school up to that point was my high intelligence. I wasn't able to study or focus at all before I was diagnosed, but luckily I didn't need to study or focus in class. I just understood everything intuitively. Everything just seemed to make sense, or I could figure it out on my own. It's almost like I didn't need to be taught something to understand it. Of course, intelligence only carries you so far, and school gets harder the more you advance. By the time I was diagnosed with adhd, I really needed to be able to focus and study to keep up with school.