This article demonstrates how feminist posthumanism can reconfigure conceptualisations of, and practices with, 'child' in Montessori early childhood contexts. It complicates Montessori's contemporary reputation as a 'middle-class phenomenon' by returning to the earliest Montessori schools as a justice-oriented project for working-class children and families. Grappling with the contradictions and inconsistencies of Montessori thought, this article acknowledges the legacy of Montessori's feminism while also situating her project within the wider colonial capitalist context in which it emerged. A critical engagement with Montessori education unsettles modernist conceptualisations of 'child' and its civilising agenda on minds and bodies. Specifically, Montessori child observation (as a civilising mission) is disrupted and reread from a feminist posthumanist orientation to generate more relational, queer and expansive accounts of how 'child' is produced through observation. Working with three 'encounters' from fieldwork at a Montessori nursery, the authors attend to the material-discursive affective manifestation of social class, gender, sexuality and 'race', and what that means for child figurations in Montessori contexts. They conclude by embracing Snaza's 'bewildering education' to reach towards different imaginaries of 'child' that are not reliant on dialectics of 'human' and 'non-human', and that allow 'child' to be taken seriously, without risking erasure of fleshy, leaky, porous, codified bodies in Montessori spaces.