Harbor Day School, located in Newport Beach, California, stands as a notable institution with a rich history and a commitment to providing a well-rounded and progressive education. Established in 1952 as part of the Episcopal Parish of St. James, it has the distinction of being Orange County's oldest independent school. The school initially opened with 51 students and was led by a parish priest. Its founding was driven by a group of dedicated parents who sought an independent education for their children.

By 1968, Harbor Day School was officially incorporated as a non-profit institution under California charter, marking its transition to an independent school. This period also saw the school receiving accreditation by the California Association of Independent Schools (CAIS) and the National Association of Independent Schools (NAIS), further solidifying its standing in the educational community.

The school's history is marked by significant milestones and growth. In 1972, groundbreaking on a new six-acre campus on Pacific View Drive began, which led to the opening of the school at this location in 1973. This expansion was part of a master plan developed after the State Highway Division forced the closure of the previous campus. The new campus featured a library at its heart, with a cozy, ski lodge-like ambiance, complete with a wood-burning fireplace, embodying the warmth and community spirit of the school.

Over the years, Harbor Day has expanded its facilities and programs. For instance, in 1996, the Board of Trustees unanimously agreed to construct an 8,000-square-foot facility for specialty subjects like music, art, science, and woodshop, known as The Linden Family Arts and Science Center. Additionally, the school has a history of emphasizing community service, international cultural awareness, and fostering a sense of global responsibility among its students.

In recent years, the school has continued to innovate and expand. In 2019, the Newport Beach City Planning Commission approved the building plans for Phase I of a new campus project. This phase introduced a 66,000-square-foot main building, featuring state-of-the-art classrooms, outdoor learning spaces, and a cutting-edge STEAM wing. By 2023, the school completed the final phase of its new school building, which included a theater, gymnasium, athletic field, music classrooms, and other modern facilities, significantly enhancing the educational experience for its students.

Throughout its history, Harbor Day School has remained committed to providing an academically challenging and balanced education in a nurturing and inclusive family-centered environment. The school places a strong emphasis on developing strong moral character, curiosity, confidence, and perseverance in its students, while celebrating diversity, traditions, collaboration, and community.