Le plus souvent, on utilise simplement finir pour « end up ».

• If you keep getting in trouble, you may end up in jail.

  Tu risques de finir/de te retrouver en prison.

• With good marks, you may end up studying in Harvard.

  …, tu finiras/réussira peut-être par/à étudier à Harvard

• You’ll end up in the hospital if you don’t keep your seatbelt on.

  Tu finiras/termineras à l’hopital si…

You could use se retrouver in a lot of places where you say end up in English.

Si tu n’arrêtes pas tes bêtises, tu vas te retrouver en prison!

Vous allez vous retrouver à l’hôpital si vous ne bouclez pas votre ceinture.

I think this is more often used with a negative/unwanted place/situation to end up in, probably a bit more so than how you use to end up in English.
In speech, you can even go for a bit of redundancy to mark your point:

Si tu continues à avoir de si bonnes notes, tu vas finir par te retrouver à Harvard!

(Even if the outcome is, in fact, desirable, which I presume is the case above.)

The above is slightly informal. In more formal contexts, simply using the verb finir, suitably conjugated, will work just fine as jlliagre mentions.

Aboutir is actually the verb you are looking for in this case.

Ex: Si tu ne respectes pas les lois, tu va aboutir en prison.