The present study evaluates a prospective observer form of the Coping Inventory for Stressful Situations (CISS) by comparing the two forms in terms of factor structure, mean differences, reliability, and examining correlations between self-report and peer ratings. A total of 163 pairs of friends complete the CISS and an observer form of the CISS. Confirmatory factor analysis results indicate that for both rating forms, the four-factor solution fits better. Although self-rating data fit the theoretical model better, the peer ratings show higher reliability. The correlation between self and peer latent factors is moderate for Avoidance-oriented coping and for its subscales, but low for Task- and Emotion-oriented coping. Internal consistency coefficients for the CISS scales are high across type of rating, and a significant cross-form mean difference is found on the Task latent factor. Overall, the results provide evidence of substantial measurement equivalence between the self-rating form and the observer form, and the authors propose its use in dispositional coping research. (Contains 3 tables.)