"Working theories" encompass children's theorising about the social and material worlds. This article looks explicitly at power relations involved in pedagogy around children's working theories by focusing on the teacher's control of what and whose working theories get unpacked and extended. From an analysis of four cases from early childhood education (ECE) settings, it is concluded that teaching strategies are related to possible risks of unpacking and extending children's working theories. From a teacher's perspective such risks include: undermining the ECE setting's rules; exposing one's own lack of knowledge or skills; or risking the relations and atmosphere in the group or setting. These risks affect how working theories are dealt with in terms of time--right away, later or never--and voicing, as teachers regulate children's ideas for example through making concrete, reconstructing or silencing them.