Evaluation data helps inform decision-makers about the time, human capital, and funding required for professional learning to be effective. Evaluation data also guides program improvement and sets leaders' expectations for ongoing monitoring and accountability. The complexities of the educational systems in which professional learning happens mean there are multiple factors that could potentially contribute to changes in teacher and student outcomes, making it difficult to isolate the effects of the adult learning. Fortunately, there are a range of strategies for collecting evidence about the impact of professional learning. This article includes a range of data sources that allow educators to collect evidence about the impact of professional learning, even in the face of funding constraints and other systemic challenges. Regardless of the methods you choose, all of these evaluation steps require time for data collection, analysis, and sharing results. Ensuring collaboration among all stakeholders is key for developing a shared understanding about what tools will be used and when, what they will measure, and how the results will be analyzed and shared. This helps set school and districtwide expectations that data will be collected, analyzed, and used consistently for the betterment of students.