While the underrepresentation of young adults in national parliaments has received attention in recent years, there is limited information on their presence in subnational parliaments. We address this gap, by examining young people’s descriptive representation in Nigeria’s subnational legislatures, especially against the NotTooYoungtoRun law, which reduced the age of candidacy for Houses of Assembly. Our analysis covering four electoral cycles showed that while the supply of young people as candidates improved after the age amendment law, this was mostly due to opportunities within minor parties. However, young adults suffer age penalties at legislative elections, with older candidates more likely to emerge as winners, whether contesting on the platform of minor or major parties. This study highlights the need for further reforms to encourage the nomination of young adults as candidates among major parties and the reduction of nomination costs. We also express the need for more logistical support for young candidates during elections.