Dormitory life is a rich blend of studying, relaxing, sleeping, and enjoying the occasional “munch out” with friends and prefects— a combination of the serious and the silly. In each dorm, five or six Senior Prefects help administer dormitory rules and serve as role models and informal advisors for other students. Faculty members are also an integral part of dorm life, as most live in apartments attached to the dormitories or close by. They are routinely available to students for extra academic help, but their doors are also open for advisee dinners or a chance just to chat. The personal interaction between and among faculty, students, and prefects helps creates a powerful family atmosphere.

Like the individuals who live in them, every dormitory at Thacher has its own architectural character and history. Some dorms have more history than others: the Upper School was built in 1889, Los Padres in 1994. Traditions such as learning dorm songs (one lively, one slow, one in Latin) illustrate the abundant spirit of residential life.

While every dorm room is furnished with a bed, desk, closet, dresser, and direct connection to the Internet, students quickly decorate their rooms to reflect their own personalities and preferences. Each student creates his or her own little haven. Of course, living in shared space comes with challenges—from sharing the laundry facilities to tolerating a roommate's choice of music—but rising to these challenges lays the foundation for meaningful and lifelong friendships.

Freshmen typically have single rooms. After that first year, students live in a combination of singles and doubles, depending on their grade and what dorm they are living in.