A sizeable literature has shown that in most high-income countries, immigrants who arrive in early childhood experience a series of socio-economic advantages over those who arrive during late childhood or adolescence. However, studies have yet to examine whether this is also true for refugees, and how the effect of age at arrival varies over their early adult life course. This is a timely question, particularly in Sweden, and many other European countries, where there has been a significant growth in asylum seeker inflows during recent years and governments are struggling with the question how best to integrate refugees and their children. Using Swedish register data, we examine the impact of age at arrival on refugee integration, by focusing on a comparison of siblings who arrive as children at different ages. The results show that arrival after early childhood constrains the acquisition of human capital, decreases the probability of obtaining citizenship, and reduces earnings prospects over time. Our findings highlight the particular integration challenges that older childhood refugees are facing and suggest the need for targeted policies to support this particularly vulnerable group.