Yes. I picked Oregon State solely because they name the actual credential for many countries. Most universities don’t. They’ll simply say something along the lines of, “We expect you to have a credential that would allow you to enter a university in your own country.”
For example, from the [University of Pennsylvania:](Preparing For Admission | Penn Admissions) *Prior to the expected date of entrance at Penn, an international applicant should have completed a program of secondary education that would enable the student to enter a university in his or her own country (e.g., A-levels, Abitur). *
New York University also spells out the name of the credential for many countries if you’d like a reference from a more selective university, though many smaller countries are missing from that list: http://cas.nyu.edu/content/nyu-as/cas/academic-programs/bulletin/policies/admission.html (Scroll down to the sentence, “The following country-specific examinations are all accepted as admission credentials”)
Many other factors will far outweigh the marginal benefit of having a high school credential that Americans know well. In particular, money. Requiring financial assistance is the largest handicap you could possibly have.
If you aspire to attend a particularly selective university, extracurricular activities become very important. Harvard once said that 90% of their applicants are qualified to attend. That means they have to use criteria other than school grades and SAT scores to pick their students.