This article explores the social meaning of Greta Thunberg. Time magazine made her Person of the Year 2019, claiming she has become a social phenomenon, a "global sensation". This article utilises psychosocial theory and new social movement theory to explore the social meaning of "Greta". It asks what "Greta" evokes in our "social imaginary" (Taylor, 2009, p. 146). What conscious and unconscious identifications are projected onto "Greta" that have made her the unlikely famous person she is? These questions are not about exploring her individual psychological, leadership, or character traits, but focus on Greta (now eighteen years old) as a social object (Latour, 2005) with a vast social network following her, including over 4.2 million Twitter followers, a new documentary film about her, and mainstream media coverage across the globe. Part one of this article outlines the context and libidinal economies that Greta operates within, and the theoretical influences the article draws upon. Part two outlines five core messages that Greta transmits, and the meanings that emerge from observing social reactions to her. The article ends with a conclusion summarising the social meanings of Greta.