In this article, I consider “alter-childhoods”: explicit attempts to imagine, construct, talk about, and put into practice childhoods that differ from perceived mainstreams. I critically examine alter-childhoods at fifty-nine alternative education spaces in the United Kingdom. I analyze alternative education spaces through the lens of biopolitics, developing nascent work in children's geographies and childhood studies around hybridity and biopower. I focus on two key themes: materialities and (non)human bodies; intimacy, love, and the human scale. Throughout the analysis, I offer a limited endorsement of the concept of alter-childhoods. Although there exist many attempts to construct childhoods differently, the “alternative” nature of those childhoods is always muddied, complicated, and dynamic. Thus, the concept of alter-childhoods is useful for examining the biopolitics of childhood and for children's geographers more generally—but only when considered as a critical tool and questioning device.