The present study investigated the relation between intolerance of uncertainty (IU), meta-worry, and neuroticism on the one hand, and worry on the other hand, in a sample of 105 university students. Two different operationalizations of worry were used: trait worry and idiosyncratic worry. Results showed that IU, meta-worry, and neuroticism correlated significantly with trait worry. Further, IU and meta-worry were strongly related but made a unique and independent contribution to trait worry. Finally, IU and meta-worry could be considered as partial mediators of the relation between neuroticism and trait-like worry. Relations of IU, meta-worry, and neuroticism with idiosyncratic worry were weak or even absent, although neuroticism was associated with idiosyncratic worry when the stressful event was more imminent. In conclusion, not IU and meta-worry, but the general vulnerability factor of neuroticism appeared to possess the most declarative value in relation to both trait and idiosyncratic worry.