From the 2012-2013 database, here are the top 5 Hawaii public high schools (excluding charter) based on 11th grade ACT scores.

Percent scoring at or above 19 on the 11th grade ACT:

Kaiser High School @ 56 percent
Mililani High School @ 54 percent
Kalaheo High School @ 52 percent
Kalani High School @ 50 percent
Moanalua High School @ 50 percent

Not surprisingly, these schools also have a high percentage of graduates going on to college, from 86 to 75 percent; Kalani topped the list reporting 86 percent of graduates continuing their education.