The relationship between income and happiness for international immigrants has been relatively unexplored. A handful of cross-sectional studies has shown that income and happiness are positively correlated after migration, and that wealthier immigrants are more satisfied with their post-migration lives than are their less privileged peers. What is unclear is if the link between income and happiness remains positive as immigrants assimilate to life in a new country. This question is the focus of our study. Using longitudinal data from over 10,000 immigrants tracked up to 30 years in the German Socio-Economic Panel Survey, we set out to provide some insight into the long-term relationship between immigrants’ self-reported life satisfaction and the level of their income in its absolute form. Longitudinal analyses revealed that immigrants who experienced increases in income over time reported greater satisfaction with life and that the income-happiness link remained relatively stable over time. The effect of absolute income on immigrants’ happiness was, nevertheless, small. We also observed that country of origin played an important role in the post-migration association between income and happiness. Income was a stronger predictor of the life satisfaction of immigrants from poorer origins than it was for their wealthier counterparts.