On April 27, 1792, fifty residents of the towns of Groton and Pepperell formed an association to raise funds for a "Publick School ... in Groton, for the education of youth, of both sexes—in which School are taught the English, Latin and Greek Languages, Writing, Arithmetic, Geography, the Art of Speaking and Writing, with Practical Geometry, and Logic.

"[1][2] The founders of the new Groton Academy included prominent citizens Oliver Prescott, Zabdiel Adams, Samuel Dana, and Timothy Bigelow.

[6] Its primary purpose was to educate students from the surrounding region; at the time, Groton was the second-largest town in Middlesex County and the center of the local economy.

[13] Turnover at the top meant that several notable individuals taught at Groton Academy after graduating from college, including Asahel Stearns, the co-founder of Harvard Law School,[14] and William Merchant Richardson, the future chief justice of the New Hampshire Supreme Court.

[15] Alumni in the early years included James Walker, president of Harvard University; John Prescott Bigelow, mayor of Boston; James Gordon Carter, a pioneer in tax-funded public schools; and Nehemiah Cutter, a co-founder of the American Psychiatric Association.

[21] Over the course of their lives, Amos and William Lawrence donated nearly $65,000 in cash, scholarships, and property to the school (around $2.6 million in 2024 dollars).

[22] The Lawrences' funds also helped the academy establish close ties with prominent liberal arts schools, including Williams College, which historically catered to New England's "older provincial elite.

[28] In 1860, the town opened Groton High School, providing the first secular alternative to Lawrence Academy.

It raised tuition to $430 (it was $200 fifteen years earlier[33]) and revised the curriculum to focus on college entrance examinations.

[37][20] It closed again from 1898 to 1899 while it converted into an all-male high school, at the expense of its first female principal, Kate Mann, hired just one year earlier.