Singing and playing musical instruments is seen as beneficial for parent–child relationships. Using longitudinal data from the German Panel Analysis of Intimate Relationships and Family Dynamics (Pairfam) we investigate the role of specific facets of parent–child relationships as predictors of family musical activity, namely Intimacy, that is, the degree of mutual sharing of thoughts and feelings, Admiration, that is, positive affirmative attitudes, and Prosocial Behavior, that is, showing empathy and consideration for others. Study 1 included responses from a total of N = 1,339 parents (71% mothers) and N = 1,783 children (52% male), and Study 2 differentiates between specific subsamples of parent–child relations. Data were submitted to a series of regression models. Study 1 showed that higher values of Intimacy were associated with greater music activities for both parent and child even when general levels of music activities decreased over time. Study 2 addressed cases in which mothers and fathers independently assessed the same child. The results showed similar patterns of association for both parents and children across studies. In addition, mothers perceived higher levels of family music activities than did fathers. Finally, high levels of Intimacy were associated with increased family music activity against the general trend of decline. Taken together, a strong and consistent pattern of a positive relationship between, on the one hand, mutual parent–child perceptions of trust and confidence, that is, Intimacy, and on the other hand, music activity, was found. These results confirm and extend earlier work to suggest a certain role of the quality of family relationships in pursuing musical activities from childhood to adolescence.