This study examines the unique contributions of parental wealth, class background, education, and income to different measures of educational attainment. We build on recent sibling correlation approaches to estimate, using Norwegian register data, the gross and net contribution of each social origin dimension across almost 3decades of birth cohorts. Our findings suggest that parental education is crucial for all measures of children's educational outcomes in all models. In the descriptive analyses, we find that while broad education measures remain stable or decrease over time, attaining higher tertiary education and elite degrees is more stable or increasingly dependent on family background, especially parental financial resources. While gross sibling correlation models show somewhat decreasing trends in the contribution of education in all measures of educational outcomes, net models show that the unique contributions of financial resources have increased over time. Our results lend some support to the idea of education as a positional good and suggest that educational inequalities reflect broader patterns of inequality in society. Our results further indicate that the importance of parental education and cultural capital for children's education can be explained by within-resource transmission but that pro-educational norms tied to wealth may play an increasingly important role in educational mobility. In summary, this study sheds light on the multidimensional nature of social origins and highlights the role of different factors in shaping educational outcomes over time.