Mercer Island High School is a public high school located in Mercer Island, Washington, United States, as part of the Mercer Island School District. As of the 2022–23 school year, the school had an enrollment of 1,524 students and 74.51 classroom teachers, for a student–teacher ratio of 20.45.
Serving 1,439 students in grades 9-12, Mercer Island High School ranks in the top 5% of all schools in Washington for overall test scores (math proficiency is top 5%, and reading proficiency is top 5%).
The percentage of students achieving proficiency in math is 81% (which is higher than the Washington state average of 41%). The percentage of students achieving proficiency in reading/language arts is 94% (which is higher than the Washington state average of 53%).
The student-teacher ratio of 19:1 is higher than the Washington state level of 17:1.
Minority enrollment is 48% of the student body (majority Asian), which is lower than the Washington state average of 53% (majority Hispanic and Asian).
Quick Facts (2026)
- Grades: 9-12
- Enrollment: 1,439 students
- Student-Teacher Ratio: 19:1
- Minority Enrollment: 48%
- Graduation Rate: 94% (Top 10% in WA)
- Overall Testing Rank: Top 5%
- Math Proficiency: 81% (Top 5%)
- Reading Proficiency: 94% (Top 1%)
- Science Proficiency: 83% (Top 5%)
- Source: National Center for Education Statistics (NCES), WA Dept. of Education
Top Rankings
Mercer Island High School ranks among the top 20% of public schools in Washington for:
Category
Attribute
Overall Rank
Math Proficiency
Reading/Language Arts Proficiency
Science Proficiency
Graduation Rate
School Overview
Mercer Island High School's student population of 1,439 students has declined by 7% over five school years.
The teacher population of 76 teachers has stayed relatively flat over five school years.
Grades Offered
Grades 9-12
(Supplemental Virtual)
(Supplemental Virtual)
Total Students
1,439 students
Total Classroom Teachers
76 teachers
Year Founded
1955
Colors
White, Maroon
School Calendar
School Rankings
Mercer Island High School ranks within the top 5% of all 2,088 schools in Washington (based off of combined math and reading proficiency testing data).
The diversity score of Mercer Island High School is 0.65, which is less than the diversity score at state average of 0.69. The school's diversity has stayed relatively flat over five school years.
Overall Testing Rank
#26 out of 2088 schools
(Top 5%)
(Top 5%)
Math Test Scores (% Proficient)
81%
41%
Reading/Language Arts Test Scores (% Proficient)
94%
53%
Science Test Scores (% Proficient)
83%
49%
Student-Teacher Ratio
19:1
17:1
Asian
25%
9%
Hispanic
7%
27%
Black
2%
5%
White
52%
47%
Hawaiian
1%
2%
Two or more races
13%
9%
All Ethnic Groups
Graduation Rate
94%
84%
Eligible for Free Lunch
5%
39%
Eligible for Reduced Lunch
3%
9%
School Statewide Testing
School District Name
Source: National Center for Education Statistics (NCES), WA Dept. of Education
School Notes
- School Mascot: Herbert The Snail
Frequently Asked Questions
What is Mercer Island High School's ranking?
Mercer Island High School is ranked #26 out of 2,088 schools, which ranks it among the top 5% of public schools in Washington.
What schools are Mercer Island High School often compared to?
Mercer Island High Schoolis often viewed alongside schools like Newport Senior High School by visitors of our site.
What percent of students have achieved state testing proficiency in math and reading?
81% of students have achieved math proficiency (compared to the 41% WA state average), while 94% of students have achieved reading proficiency (compared to the 53% WA state average).
What is the graduation rate of Mercer Island High School?
The graduation rate of Mercer Island High School is 94%, which is higher than the Washington state average of 84%.
How many students attend Mercer Island High School?
1,439 students attend Mercer Island High School.
What is the racial composition of the student body?
52% of Mercer Island High School students are White, 25% of students are Asian, 13% of students are Two or more races, 7% of students are Hispanic, 2% of students are Black, and 1% of students are Hawaiian.
What is the student-teacher ratio of Mercer Island High School?
Mercer Island High School has a student ration of 19:1, which is higher than the Washington state average of 17:1.
What grades does Mercer Island High School offer ?
Mercer Island High School offers enrollment in grades 9-12 (Supplemental Virtual).
What school district is Mercer Island High School part of?
Mercer Island High School is part of Mercer Island School District.
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