The purpose of this study was to examine the perceived conceptual differentiation between "knowledge" and "beliefs". In particular, it aimed at examining significant differences related to gender and grade level in the epistemological standards student used to distinguish the two constructs and define the possible relationships between them. The study involved 226 participants of two grade levels: 8th graders and 13th graders. Qualitative and quantitative analyses were performed. Outcomes revealed that also the younger participants were able to distinguish between knowledge and beliefs, verbalize their distinction and justify the perceived relationships between the two constructs. As hypothesized, grade level significantly differentiated the epistemological standards used for distinguishing knowledge from beliefs. The study indicates the educational importance of considering both knowledge and beliefs that students bring to a learning situation.