Mock elections are an increasingly popular form of active learning, adopted in many European countries and the United States. However, we have limited knowledge regarding the extent to which they enhance students' civic competence. This article analyzes data from over 9,000 students aged 13-19 who participated in a 2022 mock election in Sweden. The goal is to determine the extent to which mock elections boost civic competence, with an emphasis on potential variations related to gender, ethnic background, and educational stage. Results indicate that such participation positively influences students' self-reported political knowledge and, to a lesser extent, their political interest, engagement, and efficacy. Yet, the impact varies among student demographics. For instance, foreign-born students reported greater effects than their Swedish-born counterparts. Female students displayed heightened political knowledge and interest compared to males, while male students demonstrated higher political engagement. Interestingly, mock elections seemed to enhance political knowledge more in primary school students than in secondary school ones. Conversely, they had a more pronounced impact on the political interests and engagement of secondary school students. The study concludes with suggestions for future research to employ more rigorous methods to assess the influence of mock elections on civic competencies.