The word “family” tends to evoke positive images, such as “comfort” and “warmth,” but families exist in diverse forms, structures, and relationships. In recent years, inclusivity has been advocated in school education; along these lines, learning about the diversity of families is imperative as the family is inseparable from the children’s lives. However, exclusively positive representations of family are found in teaching guidelines for home economics, special subjects such as ethics, and life environment studies. This biased family image may not only exclude children who live in diverse families but also deprive pupils of the ability to recognize family-related problems and opportunities to learn about diversity. In Japanese language classes where family members are depicted but not mentioned in the explanations, the results of the analysis revealed a bias in the way family members are depicted in the teaching materials. However, elementary school Japanese classes that cater to family diversity can be envisaged using critical literacy, developed from Paulo Freire’s pedagogy, while critically reevaluating one’s idea of “family” through language.