Summary:
In zip code 06371 (Old Lyme, Connecticut), there is exactly one high school: Lyme-Old Lyme High School, which serves 367 students in grades 9–12 as part of Regional School District 18. The school is currently ranked 22nd out of 133 Connecticut high schools (83rd percentile, 4 stars), and the district is rated 22nd out of 153 districts (86th percentile, 4 stars).
The school's academic performance remains well above state averages in every subject. In 2024–2025, 91.9% of 11th graders were proficient in SAT ELA and 70.9% were proficient in SAT Math, compared to state averages of 58.0% and 31.1% respectively. In 2025–2026, ELA proficiency was 80.0% and science proficiency was 72.9%, still far above the state averages of 55.3% and 50.5%. The graduation rate is a strong 92.9%, and the school boasts a low 9.6-to-1 student-teacher ratio. Only 12.81% of students qualify for free or reduced-price lunch, and per-student spending is a high $22,213 (though this figure is from 2018–2019).
However, there are some cautionary signs. After ranking 4th in 2024–2025 and 7th in 2023–2024 (both 5-star, top 5% finishes), the school dropped to 22nd in 2025–2026. Chronic absenteeism stands at 19.8%, which is higher than the state average of 16.4% and nearly double the district-wide rate of 10.1%. With only 367 students, year-to-year fluctuations in rankings and test scores may partly reflect small cohort sizes rather than fundamental changes in school quality. Even with the recent dip, math proficiency remains extraordinary at more than double the state average, making Lyme-Old Lyme High School a consistently strong choice for families in the area.
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