Children come to understand the concept of gender and learn to differentiate roles and norms on the basis of gender in early childhood. By interacting with individuals in their social contexts (i.e., family and peers), children are taught about gender norms and expectations, and as a result, learn to negotiate their own identities within different contexts. Parents have an especially important role in how children come to understand their own gender identity, as they have the ability to shape their childrens’ behaviors by endorsing certain gender stereotypes (e.g., girls wear pink, and boys play with trucks). For young boys, their fathers are a key socialization agent in their gender development, as they convey both implicitly and explicitly, gender-appropriate ways of being. Fathers may endorse ideas of traditional masculinity, which constrain boys to conform to the expected male norms, and discourages them from engaging in perceived feminine behaviors, such as cross-gender play. Accordingly, young boys are often expected to prove their manhood by marking their masculinity against femininity, in a power struggle where they are trying to get their gender right. Based on established and current literature in the field of gender identity development and masculinity in early childhood, this qualitative study aimed to explore young boys’ existing working schema of masculinity and the role that their fathers play in shaping it. Participants included six father–son pairs, with boys (ages 4–6) and their fathers (ages 34–37). Fathers were first asked to complete an adapted version of the Child-Rearing Sex-Role Attitude Scale, which assessed their attitudes and beliefs about gender-related toys, activities, and behaviors. Semi-structured interviews were then conducted with the father–son pairs, where they participated in a series of toy-preference activities in a virtual game. Descriptive coding and content analysis were used to analyze the responses boys provided for their toy preferences. Boys reported having a more stereotyped definition of “girl toys” than of “boy toys”, as reflected in their choices of toys that they felt that only girls would like to play with. Fathers’ self-described beliefs reported on the Child-Rearing Sex-Role Attitude Scale were similarly reflected in their behaviours and comments during the interviews with their sons, such that fathers who shared stereotypical beliefs about gender-related behaviours and activities on the scale, engaged in behaviours which corresponded to their beliefs when interacting with their sons. Implications for families and educators are discussed.