We describe 2 studies designed to evaluate scores on the Multidimensional Shame-related Response Inventory-21 (MSRI-21), a recently developed instrument that measures affective and behavioral responses to shame. The inventory assesses shame-related responses in 3 categories: negative self-evaluation, fear of social consequences, and maladaptive behavior tendency. For Study 1, (N = 743) undergraduates completed the MSRI-21. Confirmatory factor analysis supported the validity of the MSRI-21 3-factor structure. Latent variable modeling of coefficient-α provided strong evidence for the internal consistency of scores on each scale. In Study 2, (N = 540) undergraduates completed the instrument along with 5 concurrent measures chosen for clinical significance. Achievement of factorial invariance supported the use of MSRI-21 scale scores to make valid mean comparisons across gender. In addition, MSRI-21 scale scores were associated as expected with scores on measures of self-harm, suicide, and other risk factors. Taken together, results of 2 studies support the internal consistency reliability, factorial validity, factorial invariance, and convergent validity of scores on the MSRI-21. Further work is needed to assess the temporal stability of the MSRI-21 scale scores, invariance across clinical status and other groupings, item-level measurement properties, and viability in highly symptomatic samples.