Girls’ diaries offer a unique window into the lives, attitudes, and perceptions of children. Not only do these contemporaneous documents offer an immediacy and levels of personal detail that other documents do not; these diaries also provide a more intimate and candid window into lives and emotions in the past, even as these personal accounts often reflect broader cultural conventions about appropriate emotional expression. This chapter explores what American girls’ diaries from the late colonial and early republican eras reveal about girls’ thoughts, aspirations, and dreams and how these documents challenge earlier assumptions about gender identity formation, which stressed the pressure on young women to be ladylike and to suppress any competitive, boisterous, or rebellious behaviors. The chapter shows that these girls spent a significant part of their time in the company of peers and engaged in many shared social activities, including shopping, walking, riding, visiting, dancing, and reading. Only later did the pressure to act as “young ladies” become a cultural imperative.