Summary:
Chelmsford has just one public high school, Chelmsford High, which serves grades 9–12 and enrolls 1,402 students as part of the Chelmsford district. Because there is only one high school in the area, there are no in-town school-to-school comparisons; the most useful comparisons are against the district, the state, and prior years.
Chelmsford High is a consistently strong school. It earned a 4-star rating in the district record and in every year of its available ranking history, and its latest rank is 48 out of 353 Massachusetts high schools, placing it in the top 14%. Its 2024–2025 graduation rate of 98.8% is above the district's 96.0%, and its 0.9% dropout rate is below the district's 2.6%. MCAS Next Generation proficiency is above the state in every reported subject and year. In 2025–2026, its largest edge was Biology End of Course at 64.14% proficient versus 37.68% statewide, a +26.46 percentage-point advantage; in 2024–2025, 10th-grade ELA was 75.43% versus 50.66% statewide.
The district as a whole performs well, so the school's margin over district averages is usually small — for example, +1.32 points in 2025–2026 ELA, +0.97 in math, and +0.74 in science, with Biology End of Course essentially level with the district (64.14 school vs. 64.16 district). Comparing matching 10th-grade results, math rose from 62.57% to 66.16% and science from 53.33% to 62.42%, while ELA declined from 75.43% to 68.47%. Note that the free/reduced lunch percentage is blank/not populated, spending data is from 2020–2021, and the student-teacher ratio of 13.9 has no district or state benchmark provided.
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