Maria Bowen Chapin opened "Miss Chapin's School for Girls and Kindergarten for Boys and Girls" in 1901. The school originally enrolled 78 students, who were taught by seven teachers. The school itself developed from an earlier educational effort in which Chapin and Alice Wetmore began a small elementary school in 1894 which was explicitly intended to prepare young girls for success at the Brearley School, which had been created 10 years earlier. Chapin ran the educational side of “Primary Classes for Girls,” while Wetmore ran the business end. The two ended their partnership in 1901, and “Miss Chapin’s School” was born.
Chapin's first high school diplomas were granted in 1908, and the last boys attended in 1917.
According to archival sources recounted in And Cheer for the Gold and Green, Chapin was an early feminist and suffragette who focused heavily on character development and who intended the school to offer the same classical education as was available to boys of that era.
Chapin remained headmistress until 1932. At her request, the name of the school changed to the Chapin School after she died, in 1934.
Sixty girls start in kindergarten, where they are divided into three classes. Each K class has two teachers, with regular use of teaching specialists (e.g., reading, Spanish, art, music, science, technology, gym, etc.)
There are about 265 girls in the Upper School (8th through 12th grades), where they are taught by 53 faculty members. Traditionally, Chapin did not make an effort to replace girls who left the school (generally for boarding and coed schools), leading to graduating classes of around 40. In recent years, girls are more readily accepted into Chapin's middle and upper schools, leading to graduating classes of around 55.
While the lower school program combines progressive and traditional characteristics, the upper school curriculum is considered to be a traditionally rigorous liberal arts program. There are multiple requirements, including at least one modern language and two years of Latin. While a small school, Chapin offers 15 Advanced Placement courses and a total of 36 elective courses in grades 10-12. Elective courses may cover topics such as neuroscience, pharmacology, directing lab or Greek. Upper school students may take up to 2 electives per trimester.
Many girls do independent studies or study abroad programs, particularly through Chapin's exchange programs with the St. Hilda’s Anglican School for Girls (Perth, Australia) and the American Community Schools (Athens, Greece). Since 2011, Chapin has worked with the Kibera School for Girls in Nairobi, Kenya, developing curriculum ideas and visiting each other's campuses. Chapin is also a charter affiliate member of the Online School for Girls (OSG), in which students can take courses offered to more than 30 girls’ schools across the country. New York Interschool courses are offered in advanced math, leadership, and ethics. Mentorship derives from multiple sources, including faculty advisors and peer leaders.
While some Chapin girls live on the Upper East Side near the school, others hail from other parts of Manhattan, as well as Brooklyn, Queens, the Bronx, New Jersey, Westchester, and Long Island.
The student-to-teacher ratio is 6.8 to 1. Twenty-one percent of the girls receive tuition assistance, amounting to over $5 million per year.
The school's motto is Fortiter et Recte (Bravely and Rightly).
The wheel on the school's seal was chosen by the school's founder because it is the symbol for Saint Catherine of Alexandria, the patron saint of philosophers, thinkers, and educated women. The students leave assembly in a wheel pattern.
Chapin was fond of plants, which led to the school's early construction of a greenhouse within the building. Lower schoolers care for its plants during holidays, and kindergarten applicants are given a Chapin plant during the interview process.
From its beginning, the Chapin School educated girls from some of the most affluent and socially prominent families in New York. At the same time, the school has long focused on the importance of serving the surrounding community and on feminism. In 1923, for example, the Alumnae Association created a babies clinic and a health clinic for the disadvantaged. Scholarship funds began to be collected during the Great Depression; proceeds of this fundraising allowed girls to continue in school despite the economic turmoil of the 1930s. Seniors (or "Twelves") were offered a course on the status and work of women beginning in the 1940s. Mildred Berendsen was headmistress during the tumultuous 1960s, and she became an early board member of A Better Chance and Early Steps, both of which had just been created to encourage and prepare students of color for private schools. She would later be involved in an even more successful program, Prep for Prep. The first African-American student enrolled at Chapin in 1967. Within three years, there would be 17 African American girls at the school. Thirty-eight percent of Chapin students in 2016 are young women of color.
The specifics of the school uniform have steadily evolved since 1914. As of 2017, the uniform depends upon the girl's grade level, but green is a recurrent sartorial theme.
Chapin has had a tradition of green/gold competitions since at least 1912. Throughout the year, but especially on the annual Field Day, these green and gold teams fiercely compete until a winner is announced at the end of each school year. Girls join their team in 4th grade—when applicable, joining the team of their mother or grandmother—and remain on the same team throughout their time at Chapin.
Commencement ceremonies have remained unchanged for a century. Girls wear white dresses and stand together with no differentiations made. No academic awards are given, and there has never been a Chapin valedictorian.
Chapin has affiliations and competitions with a variety of other New York City schools, often through New York Interschool. Chapin is most closely aligned and rivalrous, however, with the neighboring Brearley School, with which it shares some classes, after-school programs, homecoming, and a robotics team.
The building features the two-story Annenberg Library with over 45,000 volumes and rooms for multimedia and video editing. The library also contains a 3D printing and vinyl cutting room, three student study rooms, a student conference room, multiple lounge and table areas amongst the bookshelves, and a multi-media room. There is also a separate lower-school library.
Chapin girls make frequent use of Carl Schurz Park, which is located across the street from the school, as well as Asphalt Green Aquatics Center, which is six blocks away.
Chapin's 2008 construction provided new facilities for art, language, science and the greenhouse via expansion of the fifth and sixth floors and addition of the seventh and eighth floors.
New construction began in May 2015. When it is completed, Chapin will have grown from 8 to 11 stories and will have a top-floor regulation-size gymnasium to complement its four current gyms, a rooftop turf practice field and fitness center, expanded performing arts facilities, much larger dining facilities, and additional classrooms to provide more flexibility and experiential learning.