This special issue sets out to explore how marginalized children, as subjects within the field of history of education and childhood, challenge methodological and ethical considerations within historical research. In the articles of this special issue, we seek to find different methodological tools for studying these children and the different institutional practices that have marginalized them. The editorial begins with a brief overview of how history of childhood and history of education in particular, have treated children as subjects for research. Next, the editorial seeks to identify methodological and ethical dilemmas that need to be taken into account when studying histories of children who have been living in the margins of past societies, or those who have left only fragmentary traces in the existing historical records and archives. This leads to epistemological issues concerning children’s voice and agency, as well as the question of truth in the history of education.