Really the answer here depends upon whether you are talking about the public or private schools, in part. It also depends upon whether you just want to know about the system or whether you want to know about what happens in some schools. According to the SEE (Secretar?a de estado de educaci?n or Ministry of Education), there are three levels of schooling that more or less go along with K-12 education: inicial, b?sica, y media. If you would like to see more about the system and understand Spanish, you can go to their website:
Secretar?a de Estado de Educaci?n. All documents, like curricular requirements, can be found at
Educando - El Portal de la Educaci?n Dominicana - Inicio.
Inicial is anything before 1st grade, what we would call Early Childhood Education (zero to 6 yrs old). B?sica refers to elementary school: 1st through 8th grade. And Media refers to high school (what is called Bachillerato), and is the same as 9-12, but is called Primero de bachiller, Segundo de bachiller and so on. These are actually broken up into what they call two "cycles," the first for 9th and 10th grade and the second for 11th and 12th. To move from B?sica to Media (in other words 8th to 9th), a student needs to pass national exams, or Pruebas Nacionales. And to graduate from Media (quarto de bachiller--12th grade), the student also has to pass Pruebas Nacionales. (Side note, there is controversy regarding these exams. One particular scandal broke out last summer, but that's a discussion for another place.) And when they graduate from Media (12th grade), students are given the title of Bachiller.
In fact, there really isn't that much difference between the ways in which the systems are set up. Only the language is different to describe the different levels. However, of course, there is a difference in practice. I know of students who attended public schools who only finished 8th grade (at 19 years of age from being held back so many times). And there are some complicated rules about passing and failing classes (various end-of-semester chances to redo exams if a student fails). I don't want to explain those here because it's a lot of information. These rules for passing/failing are the reason that students of different ages can end up in the same classes (this happens far more often in public schools).
But, there are many American-type private schools in this country, particularly in Santo Domingo. And there is no serious difficulty managing the two systems because most of it is rather similar. The biggest difference is that the Dominican system mandates exactly which classes need to be taught to all students each year. Again, you can see this breakdown by looking at the curricular documents on the SEE websites if you're interested. This is somewhat troublesome because when the private schools have to add in more hours for English language arts, there are pretty much too many classes and not enough time in the day. And it creates the situation where students likely have to take more classes (not necessarily as much time in each class though) than students do in the US.
Anyway, I'm simplifying the situation a bit. But I'm not sure how the educational system was described to the original poster that seemed so difficult. Perhaps it seemed complicated because the person was explaining the reality in public schools rather than the system that is set up by the Secretar?a.
To summarize:
1st-8th, then exit exams to be able to move to high school
9th-12 (or primer a cuarto de bachiller), then exit exams to graduate and be able to move on to university.
Hope this helps!