#1 Best Private Schools in Union County, NJ
Mother Seton Regional High School
Diocesan school · Grades 9–12
The only Catholic school in Clark
Clark, NJ
A+Overall gradeAll girls181 students8 students per teacher
2026 lists
Best Private Schools in Union County, NJ
Private schools in Union County, NJ with the highest overall grades. Top 20 of 20 schools.
#2 Best Private Schools in Union County, NJ
Union Catholic Regional High School
Diocesan school · Grades 9–12
100% of graduates go to four-year colleges
Scotch Plains, NJ
A+Overall grade530 students10 students per teacher
#3 Best Private Schools in Union County, NJ
Oak Knoll School of the Holy Child
Independent Catholic school · Grades Pre-K–12
Smaller classes than 85% of Catholic schools nationwide
Summit, NJ
A+Overall grade498 students6 students per teacher
#4 Best Private Schools in Union County, NJ
St. Bartholomew Academy
Parish school · Grades Pre-K–8
Smaller classes than 67% of Catholic schools in New Jersey
Scotch Plains, NJ
A+Overall grade157 students11 students per teacher
#5 Best Private Schools in Union County, NJ
Flexschool
Independent school · Grades K–12
The only independent school in Berkeley Heights
Berkeley Heights, NJ
A+Overall grade98 students3 students per teacher
#6 Best Private Schools in Union County, NJ
Kent Place School
Independent school · Grades Pre-K–12
The only independent school in Summit
Summit, NJ
A+Overall gradeAll girls636 students7 students per teacher
#7 Best Private Schools in Union County, NJ
Academy of Our Lady of Peace
Parish school · Grades Pre-K–8
Smaller classes than 88% of Catholic schools in New Jersey
New Providence, NJ
A+Overall grade125 students9 students per teacher
#8 Best Private Schools in Union County, NJ
Bruriah High School for Girls
Jewish day school · Grades 6–12
The only all-girls school in Elizabeth
Elizabeth, NJ
A+Overall gradeAll girls213 students4 students per teacher
#9 Best Private Schools in Union County, NJ
Oratory Prep School
Independent Catholic school · Grades 7–12
The only all-boys school in Summit
Summit, NJ
A+Overall gradeAll boys363 students9 students per teacher
#10 Best Private Schools in Union County, NJ
St. Joseph the Carpenter School
Diocesan school · Grades Pre-K–8
Serving families in Roselle since at least 2011
Roselle, NJ
AOverall grade160 students12 students per teacher
#11 Best Private Schools in Union County, NJ
Holy Trinity
Diocesan school · Grades Pre-K–8
The only Catholic school in Westfield
Westfield, NJ
AOverall grade303 students12 students per teacher
#12 Best Private Schools in Union County, NJ
Sinai Christian Academy
Christian school (nondenominational) · Grades Pre-K–11
A Christian school in Linden
Linden, NJ
A-Overall grade67 students10 students per teacher
#13 Best Private Schools in Union County, NJ
Salahuddin Future Academy, Plainfield Branch
Islamic school · Grades Pre-K–12
Small classes: about 5 students per teacher
Plainfield, NJ
B+Overall grade70 students5 students per teacher
#14 Best Private Schools in Union County, NJ
PNS&K
Early childhood program · Grades Pre-K–K
One of the 3 largest preschools in New Jersey
Westfield, NJ
B+Overall grade69 students8 students per teacher
#15 Best Private Schools in Union County, NJ
St. Michael Parish School
Parish school · Grades Pre-K–8
Serving families in Union since at least 2011
Union, NJ
B+Overall grade329 students15 students per teacher
#16 Best Private Schools in Union County, NJ
St. Pauls Day School
Early childhood program · Grades Pre-K–K
One of the 3 largest preschools in New Jersey
Westfield, NJ
B+Overall grade70 students18 students per teacher
#17 Best Private Schools in Union County, NJ
St. Michael School
Diocesan school · Grades Pre-K–8
The only Catholic school in Cranford
Cranford, NJ
BOverall grade258 students16 students per teacher
#18 Best Private Schools in Union County, NJ
Jewish Educational Center Lower School
Jewish day school · Grades Pre-K–5
The largest Jewish school in Elizabeth
Elizabeth, NJ
BOverall grade221 students8 students per teacher
#19 Best Private Schools in Union County, NJ
Harmony Christian Academy
Christian school (nondenominational) · Grades Pre-K–11
A Christian school in Elizabethport
Elizabethport, NJ
BOverall grade83 students10 students per teacher
#20 Best Private Schools in Union County, NJ
Rav Teitz Mesivta Academy (Jec High School)
Jewish day school · Grades 6–12
The only all-boys school in Elizabeth
Elizabeth, NJ
B-Overall gradeAll boys210 students14 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.