Racial disparities in teachers' perceptions, interactions, and behaviors of students persist in the United States. Learning more about teachers' beliefs about the causes of racial inequity may help to explain the racial disparities that exist in teachers' behaviors and practice. To better understand and assess teachers' beliefs about the causes of racial inequity in the U.S., we developed and investigated the validity of the Racism and Inequity Beliefs (RIB) questionnaire. The RIB questionnaire consists of 18 items based on theory, research, and interview data with teachers related to beliefs about social and racial inequities. A sample of 228 teachers (82% White) across five school districts (3 urban; 2 rural) responded to the RIB questionnaire. Confirmatory factor analyses confirmed four scales: American Dream, Post-Racial, Cultural Deficit, and Schooling Inequity. Patterns of correlations among the RIB scales and with external measures suggested construct validity for this measure. Future directions include investigating how the four racial inequity beliefs may work to activate teachers' racialized behaviors and practices and the effects of these racialized experiences on students' learning opportunities, academic achievement, and educational trajectories.