With the overarching aim to create knowledge about children’s privacy in preschool, this doctoral study lies at the intersection of early childhood educational research and privacy studies. Given privacy’s status as a human right and democratic value in Swedish preschool, the study investigates what privacy means to children and how they regulate it in everyday interactions in preschool. Analytically, the study departs from an understanding of privacy as a social practice (Reiman, 1984/2007), and children’s privacy practices are interpreted through Irwin Altman’s (1975, 1976, 1977) privacy regulation theory with concepts such as territory and personal space. Influenced by Erving Goffman (1959/2020, 1961/2014) and Maxine Wolfe (1978; Wolfe & Rivlin, 1987) these practices are interpreted as situated in preschool as an institutional context where children are attributed a social role as preescholers. The analytical point of departure in privacy theory is new to national early childhood educational research and thus contributes new perspectives. Ethnographic fieldwork was conducted in one preschool with children aged 1—6, along with their parents and educators. Building on participant observations, interviews, and documents, the analysis identifies themes of homesickness, physical closeness, seclusion, ownership and documentation. The results show that privacy is a central part of children’s everyday social lives in preschool. Children practice privacy by attempting to control their social boundaries: they regulate social distance, ownership and information sharing based on subjective privacy preferences. Children’s privacy practices often take a “relational logic” as their starting point, one that links close relationships with physical proximity and intimacy, and vice versa. Thus, children’s boundary regulation is about selectively creating closeness and nurturing relationships as well as keeping others at a distance. Furthermore, the results provide understandings of how children’s privacy practices and relation logic conflict with and are conditioned by institutional logics that prioritise the collective over the individual, emphasising adult authority and surveillance that makes privacy difficult, often resulting in forms of “pseudo-seclusion”. Children’s own bodies, which are smaller, make it more difficult for them to assert their boundaries; this is another central condition. In summary, children practice privacy through many different practices and expressions, including ways that span over a wide range of issues and situations. Recognising privacy as part of the complexity of children’s relations is relevant across contexts, private or public, physical or digital. The study thus calls for an understanding (and pedagogy) of privacy attentive to children’s experiences.