Recent research has shown that life satisfaction is lower in states with a high neuroticism level than in less neurotic states. The present study disentangles the effect of state- and individual-level neuroticism on life satisfaction in a multilevel regression analysis using nationally representative data from 16 German federal states. The results show that controlling for individual-level neuroticism results in a reduction of the effect of state-level neuroticism on individuals’ life satisfaction, although it remains statistically and practically significant. Hence, the ecological correlation between state-level neuroticism and state-level life satisfaction reported in prior research is not a mere reflection of individual-level associations. The process of emotional contagion is proposed as the potential mechanism of the state-level neuroticism effect.