The reform movement in science, technology, engineering, and mathematics has prompted calls for research to provide a better understanding of factors related to desired learning outcomes in introductory statistics courses. However, little is known about instructor factors involved in teaching statistics. This study describes the development and validation of the Statistics Teaching Inventory (STI) designed to assess the practices and beliefs of teachers of introductory statistics courses across the disciplines. Survey data were collected from 101 instructors from different institutions in the United States. Reliability coefficients were high (>0.75) for two subscales (practice and beliefs) and item-total correlations were generally at an acceptable level (>0.30). Summaries of individual response patterns and the relationship between the beliefs and practice subscales are presented. The study concludes with limitations related to the sample size, sample characteristics, and psychometric properties based on summated scores, and suggests future research.