St. Helena Montessori was founded in 1981 by Mrs. Elena Heil and Mrs. Olga McAdam, who taught the first Montessori Primary Class. In 1985, the school expanded to include a Montessori Elementary Class. In 1989, it was incorporated as a 501(c)(3) public benefit corporation and a Board of Directors became the governing body of the school. In 2008, an Adolescent Program / Farm School was added. The Adolescent Program maintains a farm on the school’s 20-acre parcel on the east side of St. Helena, which became the permanent home to the entire school in the fall of 2013.

St. Helena Montessori offers three levels of Montessori education: a five-day-per-week Primary program for children from the age of 2 ½ years through 6 years, an Elementary program for 6 through 12 years, and an Adolescent / Farm School for 12- to 15-year-old students.