Construct validation work on Tellegen's (1982) Multidimensional Personality Questionnaire (MPQ) resulted in further inferences about Negative Emotionality. Two hundred thirty-two students were rated by three knowledgeable informants, yielding a total of 928 participants. The median monotrait correlation of MPQ primary scores with summed observer ratings was. 48, and all were significant, p <. 01. These data show higher self-report to informant rating convergences in the Positive Emotionality (Extroversion) domain than in the Negative Emotionality (Neuroticism) domain. Furthermore, in the Negative Emotionality domain, peers, mothers, and fathers were not equivalent as classes of raters. Stress Reaction ratings showed uniformly lower levels of convergence with self-report (relative to Positive Emotionality traits) across all rater classes. For Alienation, peer and maternal ratings were comparable, but paternal ratings correlated significantly less with self-report scores than did maternal ratings. And finally, with Aggression, peer ratings correlated significantly higher with self-report than either maternal or paternal ratings. These findings, taken in the context of the literature, have implications for a hierarchical model of Negative Emotionality, support inferences about the display of cues of Negative Emotionality, and offer new cautions for rating-based assessment.