Internet-based texts addressing science issues can contain inaccurate and contradictory information. However, prior research has shown that students often have difficulties in identifying contradictions in science texts. In a quasi-experimental study with treatment-control groups design with N = 129 high-school students from grades 10 and 11, we thus investigated whether a short classroom intervention could foster students' identification of contradictions in a physics text presented in a question & answer forum. Specifically, the intervention, which was provided in a regular physics lesson, was aimed at sensitizing students to the existence of inaccurate physics information on the Internet. Five weeks after the intervention, students of three intervention and three control classes were tasked to read a paper-printout of an Internet forum text on wind power plants that contained several contradictions. Subsequently, students performed a Conflict Verification Task (CVT) that measured their identification of the contradictions. The effectiveness of the intervention was moderated by students' reading comprehension skills. Students with higher reading comprehension skills benefitted from the intervention, with those in the intervention group achieving higher CVT scores than those in the control group. For students with lower reading comprehension skills, however, no differences between intervention and control group were obtained. In addition, prior domain knowledge was positively related to the identification of contradictions, independent of the intervention or students' reading comprehension skills. Theoretical and practical implications of these findings are discussed.