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St. Mary School

16 Harrison Ave East Islip, NY 11730

Quick Facts (2026-27)

  • Top Ranked NY School
  • Grades: Prekindergarten-8
  • Enrollment: 501 students
  • Application Deadline: None / Rolling
  • Source: National Center for Education Statistics (NCES)
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About the School

  • St. Mary School was established in 1914 by the School Sisters of Notre Dame.
  • Now in our ninetieth year, we continue to provide challenging academic programs rooted in the Catholic tradition for children in Nursery (3 year olds) through Grade 8.
  • The dedication and strong commitment of the administration, faculty, staff, clergy, and parents to continued growth and quality Catholic education permeates the strong family – centered school community.
  • Centered in the Word of God and the gift of Jesus in our midst, the mission of St. Mary School is to educate the whole child.
  • The school's role in leading students toward a life of Gospel values is to work in partnership with parents to foster academic, spiritual, and moral development.

Quick Facts (2026-27)

  • Top Ranked NY School
  • Grades: Prekindergarten-8
  • Enrollment: 501 students
  • Application Deadline: None / Rolling
  • Source: National Center for Education Statistics (NCES)

School Rankings

St. Mary School ranks among the top 20% of private schools in New York for:

Category
Attribute
Student Body

School Facts

Religious Affiliation
Grades Offered
Grades Prekindergarten-8
Students By Grade
School Calendar

Student Body

Total Students
501 students
Student Body Type
Co-ed
% Students of Color
32%
State avg.: 39%

Academic Profile

Total Classroom Teachers
27 teachers
Student-Teacher Ratio
19:1
National avg.:
School Membership(s)School Assoc.

Tuition & Financial Aid

Admission Deadline
None / Rolling

School Notes

  • St. Mary School was established in 1914 by the School Sisters of Notre Dame. Now in our ninetieth year, we continue to provide challenging academic programs rooted in the Catholic tradition for children in Nursery (3 year olds) through Grade 8. The dedication and strong commitment of the administration, faculty, staff, clergy, and parents to continued growth and quality Catholic education permeates the strong family – centered school community. Centered in the Word of God and the gift of Jesus in our midst, the mission of St. Mary School is to educate the whole child. The school's role in leading students toward a life of Gospel values is to work in partnership with parents to foster academic, spiritual, and moral development.
  • Sample of notable school alumni/alumnae:
    • Brendan and Tyler - Class of 2023 -
    • James and Emma - Class of 2023 -
Source: National Center for Education Statistics (NCES)

Frequently Asked Questions

Who are famous alumni from St. Mary School?
St. Mary School famous alumni include: Brendan and Tyler - Class of 2023 and James and Emma - Class of 2023.
What is St. Mary School's ranking?
St. Mary School ranks among the top 20% of private schools in New York for: Lowest average acceptance rates and Largest student body.
When is the application deadline for St. Mary School?
The application deadline for St. Mary School is rolling (applications are reviewed as they are received year-round).

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Did You Know?

The average private school tuition in Suffolk County, NY is $21,365 for elementary schools and $27,758 for high schools (read more about average private school tuition across the country).
The average acceptance rate in Suffolk County, NY is 73% (read more about average acceptance rates across the country).

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