Our article details the development of the self-report Negative Body Talk (NBT) scale and five studies (all conducted with samples of U.S. undergraduate women) supporting the psychometric soundness of scores on this measure. The NBT scale measures women’s tendency to engage in negatively valenced commentary about the weight and shape of their own bodies (including upward comparisons that comprise implicit negative commentary) when speaking with others. Two subscales were identified using a combination of exploratory and confirmatory factor analyses. The body concerns subscale assesses women’s tendency to make comments expressing worries over the size/shape of their bodies. The body comparison subscale assesses women’s tendency to vocalize unfavorable comparisons of their body with the bodies of other women. Scores on the NBT scale demonstrated strong internal consistency and moderate test–retest reliability with these samples of U.S. college women. Evidence of convergent, discriminant, and incremental validity is presented. The NBT scale may be useful in the growing body of research examining how the social norm of women expressing body dissatisfaction in conversation with others both reflects and fuels body image disturbance in women.