Research continues to find gender inequality in politics and political communication, but our understanding of the variation in the degree of bias across systems is limited. A recent meta-analysis reveals how, in countries with proportional representation (PR), the media pay considerably more attention to men politicians. In plurality systems, this bias is absent. The present study proposes a new explanation for this finding, emphasizing how the size of electoral districts moderates both the demand for and supply of women politicians in news reporting. Analyzing more than 600,000 news appearances made by Norwegian and British MPs from 2000 to 2016, we produce a detailed picture of gender biases in news visibility that speaks in favor of single-member districts in plurality systems. Although PR is generally recognized as advantageous for the political representation of women, our findings call for a more nuanced understanding of the link between electoral systems and gender equality.