The use of data to inform instructional and educational decisions is an increasingly important facet of teachers' professional practice. However, little is presently known about the best teacher learning mechanisms by which to promote data use. This study (N = 329) examined the nature and distribution of both Illinois public teacher data use practices and teacher learning for data use and how learning opportunities and other factors previously identified in the literature (e.g., leadership and teacher beliefs) relate to data use practices. Our study replicates the importance of specific teacher beliefs for data use practices, and contributes new evidence for the role of course-based learning opportunities.