Over recent decades, children’s living arrangements following parental separation have changed in Sweden. In particular, shared physical custody arrangements, where children live 50/50 with both parents, have increased. Prior studies have observed that children in these arrangements tend to be socioeconomically advantaged and report better well-being than less advantaged peers who live primarily with one parent. Consequently, the increasing prevalence of shared physical custody may have different implications for children with varying socioeconomic backgrounds, either increasing or reducing social inequalities among them. This study examines the association between socioeconomic status and post-separation living arrangements over time, focusing on shared physical custody. Using repeated cross-sectional data collected at six time points between 2002 and 2022 from the Swedish Health Behaviour in School-Aged Children survey, this study employs binary and multinomial logistic regression models to assess this relationship. The results indicate that adolescents from lower socioeconomic strata are more likely to experience parental separation and to live in mothers’ sole physical custody. Conversely, adolescents from higher socioeconomic backgrounds are less likely to experience parental separation, but if they do, they are more likely to live in shared physical custody, showing that the increasing prevalence of this arrangement is still selective in Sweden.