This study is about women's political participation in times of increased influence from radical right parties. The gender-representation gap in the Swedish radical right party, the Sweden Democrats, is examined. A reformulated contagion theory is tested using three hypotheses. To test the hypotheses, a large-N study of all of Sweden's municipalities is conducted. The results show that a large gender-representation gap exists in the Sweden Democrats party compared with that in the other main parties, and the gap has a negative effect on the total level of female representation in the municipal councils. However, the gap and the negative effect are decreasing over time in relation to the other main parties, which supports the hypotheses and the reformulated contagion theory.