Based on administrative panel data from Norway, we examine how social insurance dependency spreads within neighborhoods, families, ethnic minorities, and among former schoolmates. We use a fixed effects methodology that accounts for endogenous group formation, contextual interactions, and time-constant as well as time-varying confounders. We report evidence that social insurance dependency is contagious. The estimated network effects are both quantitatively and statistically significant, and they rise rapidly with “relational closeness” in a way that establishes endogenous social interaction as a central causal mechanism. Social interactions do not cross ethnic borders.