This study was designed to identify and analyze possible factors that mediate the effect of gender on ninth-grade Turkish students' misconceptions concerning electric circuits. A Simple Electric Circuit Concept Test (SECCT), including items with both practical and theoretical contexts, and an Interest-Experience Questionnaire about Electricity (IEQ) were administered to 1,678 ninth-grade students (764 male, 914 female) after the completion of a unit on electricity to assess students' misconceptions and interests-experiences about electricity. Results of the concept test indicated that general performances of the students were relatively low and that many students had misconceptions in interpreting electric circuits. When the data were analyzed using MANOVA and follow-up ANOVAs, a gender difference for males was observed on the dependent variable of total scores on the 10 practical items; however, there was no significant gender difference on the dependent variable of total scores on the six theoretical items. Moreover, when the same data were analyzed using MANCOVA and follow-up ANCOVAs, controlling students' age and interest-experience related to electricity, the observed gender difference was mediated on the total scores on the practical items. © 2004 Wiley Periodicals, Inc. J Res Sci Teach 41: 603–616, 2004