Equipping teachers to use data is a critical piece of the school improvement puzzle. To help early career teachers (ECT) develop data-use acumen, some districts utilize mentoring supports. While research on mentoring in general is well-developed, research on how mentoring can or does support data-informed practice is not. To address this gap, we examined perceptions about data use in a small Texas district; anticipated differences among comparison groups (i.e., mentors and non-mentors; mentors and ECT) did not emerge. We conclude that without careful selection and supports, mentors may not be able to support data-informed practice to the degree assumed.