Individual and aggregate personality traits are theoretical antecedents of psychological and workgroup climates, respectively. However, empirical research has yet to test whether or to what degree this is true. Consequently, in the domain of workplace safety, we tested emotional stability and locus of control as multilevel antecedents of safety climate. We also tested a series of homology theories to determine the degree to which personalityclimate associations are similar across organizational levels. Results revealed that both emotional stability and locus of control were meaningfully associated with safety climate at psychological and workgroup levels. In addition, multilevel homology tests demonstrated that workgroup-level personalityclimate associations were more than 2 times stronger than corresponding individual-level associations, supporting a proportional theory of homology.