Serving 340 students in grades Kindergarten-5, Cos Cob School ranks in the top 30% of all schools in Connecticut for overall test scores (math proficiency is top 30%, and reading proficiency is top 30%).
The percentage of students achieving proficiency in math is 60-64% (which is higher than the Connecticut state average of 40%). The percentage of students achieving proficiency in reading/language arts is 65-69% (which is higher than the Connecticut state average of 50%).
The student:teacher ratio of 9:1 is lower than the Connecticut state level of 12:1.
Minority enrollment is 37% of the student body (majority Hispanic), which is lower than the Connecticut state average of 53% (majority Hispanic).
Quick Stats (2025)
- Grades: Kindergarten-5
- Enrollment: 340 students
- Student:Teacher Ratio: 9:1
- Minority Enrollment: 37%
- Overall Testing Rank: Top 30% in CT
- Math Proficiency: 60-64% (Top 30%)
- Reading Proficiency: 65-69% (Top 30%)
- Science Proficiency: 55-59% (Top 50%)
- Source: National Center for Education Statistics (NCES), CT Dept. of Education
Top Rankings
Cos Cob School ranks among the top 20% of public schools in Connecticut for:
Category
Attribute
Student Attention
School Overview
Cos Cob School's student population of 340 students has declined by 17% over five school years.
The teacher population of 36 teachers has stayed relatively flat over five school years.
Grades Offered
Grades Kindergarten-5
(Supplemental Virtual)
(Supplemental Virtual)
Total Students
340 students
Gender %
Total Classroom Teachers
36 teachers
School Rankings
Cos Cob School ranks within the top 30% of all 942 schools in Connecticut (based off of combined math and reading proficiency testing data).
The diversity score of Cos Cob School is 0.56, which is less than the diversity score at state average of 0.68. The school's diversity has stayed relatively flat over five school years.
Overall Testing Rank
#215 out of 942 schools
(Top 30%)
(Top 30%)
Math Test Scores (% Proficient)
60-64%
40%
Reading/Language Arts Test Scores (% Proficient)
65-69%
50%
Science Test Scores (% Proficient)
55-59%
47%
Student : Teacher Ratio
9:1
12:1
American Indian
n/a
n/a
Asian
9%
5%
Hispanic
19%
31%
Black
1%
12%
White
63%
47%
Hawaiian
n/a
n/a
Two or more races
8%
5%
All Ethnic Groups
Eligible for Free Lunch
11%
37%
Eligible for Reduced Lunch
3%
6%
School Statewide Testing
School District Name
Source: National Center for Education Statistics (NCES), CT Dept. of Education
Profile last updated: 02/09/2025
Frequently Asked Questions
What is Cos Cob School's ranking?
Cos Cob School is ranked #215 out of 942 schools, which ranks it among the top 30% of public schools in Connecticut.
What schools are Cos Cob School often compared to?
Cos Cob Schoolis often viewed alongside schools like International School At Dundee by visitors of our site.
What percent of students have achieved state testing proficiency in math and reading?
60-64% of students have achieved math proficiency (compared to the 40% CT state average), while 65-69% of students have achieved reading proficiency (compared to the 50% CT state average).
How many students attend Cos Cob School?
340 students attend Cos Cob School.
What is the racial composition of the student body?
63% of Cos Cob School students are White, 19% of students are Hispanic, 9% of students are Asian, 8% of students are Two or more races, and 1% of students are Black.
What is the student:teacher ratio of Cos Cob School?
Cos Cob School has a student ration of 9:1, which is lower than the Connecticut state average of 12:1.
What grades does Cos Cob School offer ?
Cos Cob School offers enrollment in grades Kindergarten-5 (Supplemental Virtual).
What school district is Cos Cob School part of?
Cos Cob School is part of Greenwich School District.
School Reviews
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