A military brat (and various brat derivatives) is a person whose parent or parents have served full-time in the armed forces during the person's childhood. Conventionally, the word brat alone may be pejorative; in modern, especially American, usage, however, "military brat" is often not considered derogatory and may in fact be seen as a term of endearment. The term is used in several English-speaking countries, especially Australia, Canada, New Zealand, and the United Kingdom; but it is in the United States particularly that this term is ascribed to a collectively identifiable demographic (with extensive psychological research done on the group by the United States Department of Defense). Accordingly, this group is shaped by frequent moves, absence of a parent, authoritarian family dynamics, strong patriarchal authority, threat of parental loss in war, and a militarized family unit. While non-military families share many of these same attributes, military culture is unique because of the tightly knit communities that perceive these traits as normal. Military culture can have long-lasting effects on children.

As adults, military brats can share many of the same positive and negative traits developed from their mobile childhoods. Having had the opportunity to live around the world, military brats can have a breadth of experiences unmatched by most teenagers. Regardless of race, religion, nationality, or gender, brats might identify more with other highly mobile children than with non-mobile ones. Some can struggle to develop and maintain deep, lasting relationships, and can feel like outsiders to U.S. civilian culture. Their transitory lifestyle can hinder potential for constructing concrete relationships with people and developing emotional attachments to specific places, which may later develop into psychologically developmental disorders (Post Traumatic Stress Disorder, Avoidant Personality Disorder, Separation Anxiety Disorder, etc.). But most assimilate quickly and well as they have to do so with each move.