Hostile interpretation biases are central to the development and maintenance of anger, yet have been inconsistently assessed. The Word Sentence Association Paradigm (WSAP) was used to develop a new measure of hostile interpretation biases, the WSAP-Hostility. Study 1 examined the factor structure and internal consistency of the WSAP-Hostility, as well as its relationship with trait anger. Study 2 provided convergent and divergent validity data by examining its associations with trait anger, aggression, depression, and anxiety. Study 3 examined the relationship between WSAP-Hostility and another measure of hostile interpretation biases, as well as another word sentence association measure, in a sample of community participants. Study 4 also used a sample of community participants to offer further evidence of convergent validity. Across the studies, the WSAP-Hostility demonstrated convergent and divergent validity and internal consistency, supporting its use as a measure of hostile interpretation biases.