The conceptual understanding related to being a citizen involves not only the explicit knowledge acquired through explicit instruction and course books but also the implicit, experiential knowledge acquired in socio-cultural and political environments. Explicit and implicit conceptual knowledge we have acquired about being a citizen affects our values, attitudes and behaviours we demonstrate as citizens. The purpose of this study is to investigate secondary school seventh grade students' implicit and explicit knowledge about the concept of citizen. The study adopted a convergent parallel mixed method. 27 students were chosen using typical case sampling for the identification of implicit knowledge, and 124 students were chosen using simple random sampling method for the identification of explicit knowledge. Data were collected from secondary school seventh grade students who were enrolled in three state schools, who had their parents' consent and who volunteered to participate in the study. Implicit knowledge about the concept of citizen was identified using the repertory grid technique, and explicit knowledge was identified using the "Explicit Knowledge Test" about the concept of citizen including seven open-ended questions. Qualitative data obtained for implicit knowledge were analyzed using content analysis methods and Idiogrid 2.4 program. Students' answers given in the explicit knowledge test were analyzed using a holistic rubric. Analysis of the data included the use of frequencies, percentages, arithmetic means, standard deviation, t-test, and one-way ANOVA.