#1 Best Private Schools in Ada County, ID
Riverstone International School
Independent school · Grades Pre-K–12
The smallest classes of any independent school in Boise
Boise, ID
A+Overall grade349 students5 students per teacher
2026 lists
Best Private Schools in Ada County, ID
Private schools in Ada County, ID with the highest overall grades. Top 14 of 14 schools.
#2 Best Private Schools in Ada County, ID
St. Marys School
Diocesan school · Grades Pre-K–8
Smaller classes than 92% of Catholic schools in Idaho
Boise, ID
A+Overall grade109 students6 students per teacher
#3 Best Private Schools in Ada County, ID
St. Marks Elementary School
Parish school · Grades Pre-K–8
Serving families in Boise since at least 2011
Boise, ID
AOverall grade323 students14 students per teacher
#4 Best Private Schools in Ada County, ID
Boise State University Trio Upward Bound
Alternative school · Grades 9–11
One of the most diverse private schools in Idaho
Boise, ID
A-Overall grade80 students6 students per teacher
#5 Best Private Schools in Ada County, ID
Montessori Academy
Montessori school · Grades Pre-K–6
One of the 3 largest Montessori schools in Idaho
Eagle, ID
B+Overall grade62 students10 students per teacher
#6 Best Private Schools in Ada County, ID
St. Joseph's Catholic School
Diocesan school · Grades K–8
One of the 3 largest Catholic schools in Idaho
Boise, ID
B+Overall grade367 students15 students per teacher
#7 Best Private Schools in Ada County, ID
Boise Valley Adventist School
Seventh-day Adventist school · Grades Pre-K–8
Growing: enrollment up 42% since 2011–12
Boise, ID
BOverall grade75 students13 students per teacher
#8 Best Private Schools in Ada County, ID
Sacred Heart Catholic School
Diocesan school · Grades Pre-K–8
Growing: enrollment up 39% since 2011–12
Boise, ID
BOverall grade195 students15 students per teacher
#9 Best Private Schools in Ada County, ID
Bishop Kelly High School
Diocesan school · Grades 9–12
The largest of 17 Catholic schools in Idaho
Boise, ID
BOverall grade967 students16 students per teacher
#10 Best Private Schools in Ada County, ID
Calvary Christian School
Christian school (nondenominational) · Grades Pre-K–8
Growing: enrollment up 103% since 2011–12
Boise, ID
BOverall grade223 students13 students per teacher
#11 Best Private Schools in Ada County, ID
Calvary Meridian Prep Academy
Christian school (nondenominational) · Grades K–10
One of the most diverse private schools in Idaho
Meridian, ID
BOverall grade185 students15 students per teacher
#12 Best Private Schools in Ada County, ID
One Stone
Independent school · Grades 9–12
One of 3 independent schools in Boise
Boise, ID
BOverall grade87 students36 students per teacher
#13 Best Private Schools in Ada County, ID
St. Ignatius Catholic School
Diocesan school · Grades Pre-K–8
The only Catholic school in Meridian
Meridian, ID
B-Overall grade428 students18 students per teacher
#14 Best Private Schools in Ada County, ID
Cole Valley Christian Schools-Secondary
Christian school (nondenominational) · Grades Pre-K–12
The largest of 52 Christian schools in Idaho
Meridian, ID
B-Overall grade1,263 students16 students per teacher
Grades compare each school's official facts, such as class size, how long it has served families and where graduates go, with similar schools. They're a starting point: visit, ask questions and trust what you see.