Without fully knowing the situation, I would say "that depends". In this case, it depends on what you are planning to do instead of going to university. Are you planning on starting your own business, or going into a trade such as welding that does not require a degree, be a farmer, or doing something else that is a reputable career that does not depend on university? In that case, I would say that you are safe in disobeying them; a parent may wish for you to become a doctor, but if you do not want to become a doctor, there is no harm in that.
If you are not going to university because you wish to become a professional gambler, run a bar, play World of Warcraft and farm virtual gold for a living, or do something that is against Islam, I would highly suggest listening to your parents. But if you do not wish to go to university "for a good reason" - and I have to say that without knowing your reasoning, which is why I put it in quotes - then I do not believe there is harm in that, may Allah forgive me if I am mistaken.