Young people are underrepresented in political institutions globally, including Japan, where less than 10% of elected positions are held by adults under 40, despite nearly a third of the voting-age population being under 40. This underrepresentation is not due to voter biases against young candidates, but rather institutional barriers and low youth turnout. A study conducted in Japan using survey experiments found that voters in Japan are equally likely to support younger and middle-aged candidates, but strongly dislike older candidates. Young voters particularly prefer young candidates, suggesting that higher youth turnout could increase youth representation. Conversely, elderly candidates are universally panned, seen as the least competent and least electable. The study challenges the idea that age biases among voters are responsible for youth underrepresentation, instead suggesting that voters are willing to support young candidates. The findings indicate that institutional barriers and low youth turnout are more significant factors in the underrepresentation of young politicians. The study also highlights the role of age stereotypes in voter evaluations, with younger candidates seen as more likely to focus on issues like education, childcare, and climate change, while older candidates are seen as more competent and electable. The results suggest that reducing institutional barriers and encouraging young people to run for office could lead to greater youth representation in public office. The study also notes that age biases may be more pronounced in local elections, where age norms are strong and the electorate is aging. The findings have implications for other advanced democracies facing similar demographic challenges.Young people are underrepresented in political institutions globally, including Japan, where less than 10% of elected positions are held by adults under 40, despite nearly a third of the voting-age population being under 40. This underrepresentation is not due to voter biases against young candidates, but rather institutional barriers and low youth turnout. A study conducted in Japan using survey experiments found that voters in Japan are equally likely to support younger and middle-aged candidates, but strongly dislike older candidates. Young voters particularly prefer young candidates, suggesting that higher youth turnout could increase youth representation. Conversely, elderly candidates are universally panned, seen as the least competent and least electable. The study challenges the idea that age biases among voters are responsible for youth underrepresentation, instead suggesting that voters are willing to support young candidates. The findings indicate that institutional barriers and low youth turnout are more significant factors in the underrepresentation of young politicians. The study also highlights the role of age stereotypes in voter evaluations, with younger candidates seen as more likely to focus on issues like education, childcare, and climate change, while older candidates are seen as more competent and electable. The results suggest that reducing institutional barriers and encouraging young people to run for office could lead to greater youth representation in public office. The study also notes that age biases may be more pronounced in local elections, where age norms are strong and the electorate is aging. The findings have implications for other advanced democracies facing similar demographic challenges.