Aim. The aim of the article is to show how taking into account the humanistic coefficient can influence the study of the ethnotheory of upbringing. It shows what the ethnotheory of upbringing is. The concept of ethnotheory of upbringing arose from the research of the development niche by Sara Harkness and Charles Super. They claimed that, apart from physical, social, and cultural factors, an important element of a child’s educational environment are the views of its guardians on upbringing. The basic features characterizing the ethnotheory of upbringing are descibed. Firstly, it concerns the broadly understood sphere of upbringing. Secondly, it is treated as obvious and indisputable. Thirdly, it is shared not only by individuals, but by the entire community within which caregivers function. The theoretical context in which this issue appeared was indicated. These included, on the one hand, ethnographic research, and on the other, various types of research on everyday thinking. Methods and materials. The work uses the concepts of developmental niche and ethnocultural upbringing expounded by S. Harkness and C. Super, as well as the concept of the humanistic coefficient expounded by Florian Znaniecki. Results and conclusion. The article recalls the concept of the humanistic coefficient presented by Florian Znaniecki. Its fundamental role in social and cultural research was shown. Possibilities of deepening research on ethnotheories of upbringing by referring to this concept were indicated. Firstly, it would be about reconstructing the internal layout of an environment that believes in a certain type of ethnotheory. Secondly, to show the attitudes of this type of environment towards other elements of the upbringing environment.