[4] [5] In the mid 1980s, North Bay Secondary School split into two schools; Orinda Academy/North Bay Secondary School [6] and North Bay Marin School[7] but remained a single corporation with a single Board of Directors.

In 1998, Orinda Academy legally separated from the North Bay Marin School.

The school is named after the city of Orinda in which it is located.

[8][9] In the spring of 2018, Ron Graydon, the founder of Orinda Academy and Head of School for 36 years retired.

[10] In June 2022, Nancy Rowland became the third Head of School.