While picture books and read-aloud activities are recognized as tools for fostering disciplinary sense-making among young learners, little attention has been paid to the implicit influences of geopolitical colonial power (Mignolo, 2009) and settler colonialism (Bang et al., 2014; Marin et al., 2020) during such interactions. This study draws on sociocultural theory of mediation (Vygotsky, 1978; see also Cole, 1996; Esmonde, 2016) and the conceptual framing of ideologies-in-pieces (Philip, 2011) to examine the dynamic mediation and construction of the geopolitical colonial matrix of power and identity in early science and mathematics learning (Takeuchi, 2021) from the perspective of critical sociocultural theory. Employing critical and decolonial interaction analysis (Marin, 2020; Philip & Gupta, 2020) and critical discourse analysis (Fairclough, 2003), this study examines how young students (primarily Asian children) and a teacher understand science and mathematics concepts by responding to the taken-for-granted pieces of colonial ideologies inscribed in picture books in a Canadian kindergarten classroom. Findings reveal how racialized children perpetuate, subtly disrupt, and negotiate colonial ideologies circulated in/through collective reading activities. The study contributes to understanding the role of colonial ideologies in mediation, and questions the assumed neutrality of young learners’ disciplinary learning through classroom-based science and mathematics picture books reading activities, toward equity in early learning.