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Cos Cob School

Q: Is Cos Cob School a good school?

Cos Cob School ranks 156 th of 493 Connecticut elementary schools. SchoolDigger rates this school 3 stars out of 5.

Public Grades PK, KG-5

156^th

SchoolDigger Rank ?

of 493 Connecticut Elementary Schools

Better than 68% of Connecticut elementary schools

Summary

Cos Cob School is an elementary school serving 340 students in grades K-5 in Cos Cob, Connecticut. The school is part of the Greenwich School District, which is ranked 16th out of 156 districts in the state and has a 5-star rating from SchoolDigger. While Cos Cob School consistently ranks in the top half of Connecticut elementary schools, with a 3-star rating, its academic performance is generally above the state average but below the district average.

One area of concern is the school's increasing chronic absenteeism rate, which has risen from 8.3% in 2021-2022 to 20% in 2022-2023, significantly higher than the district average of 10.7%. Additionally, the school's performance for its white student population has been relatively lower, ranking 116th out of 262 Connecticut elementary schools in 2022-2023, suggesting potential equity issues that need to be addressed. In contrast, Cos Cob School has shown strong performance for its special education students, ranking 32nd out of 371 Connecticut elementary schools in this category for the 2020-2021 school year.

Compared to nearby high-performing schools, such as North Mianus School and Riverside School, Cos Cob School's academic performance, as measured by SBAC test scores, is lower. These neighboring schools consistently rank among the top elementary schools in Connecticut and have significantly higher proficiency rates in English Language Arts and Mathematics. While Cos Cob School's spending per student is higher than the state average, it is lower than some of these high-performing schools, which may indicate a need to review the allocation of resources to support student success.

343

Students ?

10.0

Student/teacher ratio ?

$30,090

Per pupil spending ?

16%

Free/discounted lunch ?

300 East Putnam Ave.
Cos Cob, CT 06807

(203) 869-4670

District: Greenwich School District

Students who attend Cos Cob School usually attend:

Middle:	Central Middle School
High:	Greenwich High School

Racial breakdown:

White:

67.3%

Hispanic:

20.4%

Asian:

5.2%

See top rated Connecticut elementary schools

Compare Cos Cob School to nearby elementary schools!

At a glance

▬ Ranking trend: Holding steady — 68th percentile in 2015 → 68th in 2025

Strengths

✓Test scores above the Connecticut average (66% vs 50% meeting standards)

✓Above the Connecticut median (68th percentile)

✓Small classes — about 10 students per teacher

Worth a look

!Some student groups rank well below the school's overall statewide standing

!Near the bottom of Greenwich School District's ranking

Students meeting standards (2024-2025) ?

This school66%

District avg82%

Connecticut avg50%

156^th of 493

Connecticut public elementary schools ?

Top 32%▬ steady since 2015

See the entire ranking list of Connecticut Elementary Schools →

★★★★★

SchoolDigger rating ?

10^th of 11Elementary Schools in the Greenwich School District

16^th of 156Greenwich School District among Connecticut districts

Statewide rank percentile over time (100 = the top-ranked school in the state; click a legend item to add a student group)

Show full rank history (all student groups)

All Students

Year	Avg score	Statewide rank	Connecticut percentile	Rating
2025	73.0	156 of 493	68.4%	★★★☆☆
2024	72.0	159 of 497	68.0%	★★★☆☆
2023	77.0	131 of 491	73.3%	★★★★☆
2022	75.1	134 of 490	72.7%	★★★★☆
2021	81.7	110 of 538	79.6%	★★★★☆
2019	79.8	123 of 522	76.4%	★★★★☆
2018	74.0	156 of 532	70.7%	★★★★☆
2017	75.5	147 of 519	71.7%	★★★★☆
2016	73.3	150 of 518	71.0%	★★★★☆
2015	73.8	177 of 551	67.9%	★★★☆☆
2013	75.2	164 of 557	70.6%	★★★★☆
2012	70.8	210 of 564	62.8%	★★★☆☆
2011	75.1	158 of 565	72.0%	★★★★☆
2010	70.6	212 of 579	63.4%	★★★☆☆
2009	72.9	190 of 566	66.4%	★★★☆☆
2008	71.8	201 of 565	64.4%	★★★☆☆
2007	70.7	223 of 568	60.7%	★★★☆☆
2006	69.8	223 of 570	60.9%	★★★☆☆

Female

Year	Avg score	Statewide rank	Connecticut percentile	Rating
2023	75.8	76 of 230	67.0%	★★★☆☆
2022	70.0	94 of 234	59.8%	★★★☆☆
2021	80.0	93 of 455	79.6%	★★★★☆
2019	66.2	100 of 242	58.7%	★★★☆☆
2018	65.8	109 of 259	57.9%	★★★☆☆

Male

Year	Avg score	Statewide rank	Connecticut percentile	Rating
2023	72.6	82 of 231	64.5%	★★★☆☆
2022	69.6	93 of 232	59.9%	★★★☆☆
2021	76.9	109 of 445	75.5%	★★★★☆
2018	67.4	111 of 262	57.6%	★★★☆☆

Special Education

Year	Avg score	Statewide rank	Connecticut percentile	Rating
2021	85.6	32 of 371	91.4%	★★★★★

White

Year	Avg score	Statewide rank	Connecticut percentile	Rating
2025	46.2	160 of 248	35.5%	★★☆☆☆
2024	47.8	162 of 250	35.2%	★★☆☆☆
2023	61.8	116 of 262	55.7%	★★★☆☆
2022	64.5	105 of 252	58.3%	★★★☆☆
2021	70.5	92 of 327	71.9%	★★★★☆
2019	66.6	98 of 295	66.8%	★★★☆☆
2018	57.2	144 of 296	51.4%	★★★☆☆

How student groups rank statewide ? (each group's percentile vs the same group at other schools — higher is better; the +/- beside each compares the group with this school's overall percentile)

Special Education (2021)91st percentile+12 vs school

Female (2023)67th percentile-6 vs school

Male (2023)65th percentile-9 vs school

White (2025)35th percentile-33 vs school

By subject vs Connecticut (2024-2025) ?

Mathematics69%+20 vs state

English Language Arts62%+11 vs state

★

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Schools Near Cos Cob School

Choose columns to see: Summary School Students/Teachers Ranking Test Scores Finance All

School													Students/Teachers											Ranking (2025)				Ranking (2024)				NGSS Science (2025)		SBAC English Language Arts (2025)						SBAC Mathematics (2025)					Per Pupil Expenditures (2025)
Name	Type	Grades	Address	City	Zip	County	District	Is Charter	Is Magnet	Is Virtual	Is Title I	Phone	Enrollment	Full-time Teachers	Student/ Teacher Ratio	Free/Discounted Lunch Recipients	White	Black	Hispanic	Asian	American Indian	Pacific Islander	Two or More Races	Average Standard Score (2025)	Statewide Rank (2025)	State Percentile (2025)	SchoolDigger Rating (2025)	Average Standard Score (2024)	Statewide Rank (2024)	State Percentile (2024)	Rank Change from Previous Year	NGSS Science 5th Grade	NGSS Science 8th Grade	SBAC English Language Arts 3rd Grade	SBAC English Language Arts 4th Grade	SBAC English Language Arts 5th Grade	SBAC English Language Arts 6th Grade	SBAC English Language Arts 7th Grade	SBAC English Language Arts 8th Grade	SBAC Mathematics 3rd Grade	SBAC Mathematics 4th Grade	SBAC Mathematics 5th Grade	SBAC Mathematics 6th Grade	SBAC Mathematics 8th Grade	Total
Cos Cob School	Public	PK, KG-5	300 East Putnam Ave.	Cos Cob	06807	Western Connecticut Planning Region	Greenwich School District	No	No	No	No	(203) 869-4670	343	34	10.0	16.0%	231 (67.3%)	4 (1.2%)	70 (20.4%)	18 (5.2%)	2 (0.6%)	0 (0.0%)	18 (5.2%)	73	156^th of 493 public elementary schools	68.4%		72	159^th of 497 public elementary schools	68.0%	3			58.3	66.0	61.7				73.3	72.3	61.7			$30,090
Riverside School	Public	K-5	90 Hendrie Ave.	Riverside	06878	Western Connecticut Planning Region	Greenwich School District	No	No	No	No	(203) 637-1440	440	37	11.7	1.6%	314 (71.4%)	0 (0.0%)	80 (18.2%)	23 (5.2%)	1 (0.2%)	0 (0.0%)	22 (5.0%)	96.1	3^rd of 493 public elementary schools	99.4%		95.8	1^st of 497 public elementary schools	99.8%	2	87.2			88.3	96.2					93.5	93.6			$25,196
Julian Curtiss School	Public	PK, KG-5	180 East Elm St.	Greenwich	06830	Western Connecticut Planning Region	Greenwich School District	No	No	No	Yes	(203) 869-1896	236	28	8.3	39.0%	100 (42.4%)	12 (5.1%)	81 (34.3%)	21 (8.9%)	0 (0.0%)	0 (0.0%)	22 (9.3%)	84	73^rd of 493 public elementary schools	85.2%		70.1	171^st of 497 public elementary schools	65.6%	98			65.6	71.4	80.0				87.5		66.7			$34,301
International School At Dundee	Public	K-5	55 Florence Rd.	Riverside	06878	Western Connecticut Planning Region	Greenwich School District	No	No	No	No	(203) 637-3800	342	30	11.2	10.5%	157 (45.9%)	3 (0.9%)	64 (18.7%)	87 (25.4%)	0 (0.0%)	0 (0.0%)	31 (9.1%)	91.6	19^th of 493 public elementary schools	96.1%		90.5	32^nd of 497 public elementary schools	93.6%	13	91.5		76.8						81.2	87.0				$27,915
North Mianus School	Public	K-5	309 Palmer Hill Rd.	Riverside	06878	Western Connecticut Planning Region	Greenwich School District	No	No	No	No	(203) 637-9730	423	41	10.2	2.8%	277 (65.5%)	2 (0.5%)	53 (12.5%)	60 (14.2%)	1 (0.2%)	0 (0.0%)	30 (7.1%)	96.3	1^st of 493 public elementary schools	99.8%		95	4^th of 497 public elementary schools	99.2%	3	89.4		93.6	88.3	90.6				94.9	92.2	96.5			$25,677
North Street School	Public	PK, KG-5	381 North St.	Greenwich	06830	Western Connecticut Planning Region	Greenwich School District	No	No	No	No	(203) 869-6756	411	38	10.8	4.4%	306 (74.5%)	3 (0.7%)	56 (13.6%)	18 (4.4%)	0 (0.0%)	1 (0.2%)	27 (6.6%)	93.8	8^th of 493 public elementary schools	98.4%		90.9	26^th of 497 public elementary schools	94.8%	18			87.3	91.7	91.7				87.3	79.2				$24,905
Old Greenwich School	Public	PK, KG-5	825 Sound Beach Ave.	Old Greenwich	06870	Western Connecticut Planning Region	Greenwich School District	No	No	No	No	(203) 637-0150	385	37	10.5	2.3%	323 (83.9%)	0 (0.0%)	29 (7.5%)	15 (3.9%)	0 (0.0%)	0 (0.0%)	18 (4.7%)	95.7	4^th of 493 public elementary schools	99.2%		91.8	20^th of 497 public elementary schools	96.0%	16	90.5		91.7	89.3	93.7				90.0	89.3	85.7			$26,372
Westover School	Public	K-6	412 Stillwater Ave.	Stamford	06902	Western Connecticut Planning Region	Stamford School District	No	No	No	Yes	(203) 977-4572	624	57	11.0	60.1%	116 (18.6%)	109 (17.5%)	299 (47.9%)	69 (11.1%)	1 (0.2%)	0 (0.0%)	30 (4.8%)	35.1	304^th of 493 public elementary schools	38.3%		39.1	289^th of 497 public elementary schools	41.9%	15	42.9		37.8	57.0	46.4	45.7			34.6	40.7	34.5	34.6		$24,829
Hamilton Avenue School	Public	PK, KG-5	184 Hamilton Avenue	Greenwich	06830	Western Connecticut Planning Region	Greenwich School District	No	No	No	Yes	(203) 869-1685	299	38	7.9	59.9%	92 (30.8%)	13 (4.3%)	167 (55.9%)	9 (3.0%)	3 (1.0%)	0 (0.0%)	15 (5.0%)	69.2	177^th of 493 public elementary schools	64.1%		39.7	287^th of 497 public elementary schools	42.3%	110				67.5	71.8				54.1	55.0	71.8			$33,736
Stamford Charter School for Excellence	Public, Charter	PK, KG-8	1 Schuyler Ave.	Stamford	06902	Western Connecticut Planning Region	Stamford Charter School for Excellence District	Yes	No	No	Yes	(203) 989-0000	543	19	28.5	55.6%	15 (2.8%)	219 (40.3%)	170 (31.3%)	118 (21.7%)	4 (0.7%)	1 (0.2%)	16 (2.9%)	84.8	69^th of 493 public elementary schools	86.0%		85.5	67^th of 497 public elementary schools	86.5%	2	56.9	53.7	78.7	89.8	74.1	70.9	81.6	69.1	85.2	78.0	67.2	70.9	61.1	$11,837

Frequently Asked Questions about Cos Cob School

Is Cos Cob School a good school?

Cos Cob School ranks 156^th of 493 Connecticut elementary schools. SchoolDigger rates this school 3 stars out of 5.

What district is Cos Cob School in?

Greenwich School District

How many students attend Cos Cob School?

In the 2024-25 school year, 343 students attended Cos Cob School.

What schools do graduates of Cos Cob School attend?

Students who attend Cos Cob School usually go on to attend:

Middle : Central Middle School
High : Greenwich High School

What is the racial makeup of Cos Cob School?

Students at Cos Cob School are 67% White, 20% Hispanic, 5% Asian, 5% Two or more races, 1% African American.

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SchoolDigger data sources: National Center for Education Statistics, U.S. Department of Education, the U.S. Census Bureau and the Connecticut Department of Education.

IMPORTANT DISCLAIMERS: Not all boundaries are included. We make every effort to ensure that boundaries are up-to-date. But it's important to note that these are approximations and are for general informational purposes only. To verify legal descriptions of boundaries or school locations, contact your local tax assessor's office and/or school district.