Wikipedia
A Menntaskóli is an Icelandic equivalent to a gymnasium ( high school), although it works differently from other countries.
In Iceland grade school (grunnskóli) goes from 1st to 10th grade, which are the only mandatory school years in Iceland. After graduation from grade school, students choose what High Schools/College they wish to go to (this is similar to choosing a college in the United States). It is all based on what students wish to learn. It is a 4-year term; roughly the equivalent of the last three years of high school and the first year of university in the United States. A completion of menntaskóli usually provides the student with stúdentspróf (upper secondary certificate) which is required for entry to most university programs in Iceland. Stúdentspróf is somewhat equivalent to a JR college diploma in the US.