The call for school psychologists to demonstrate accountability in the evaluation of services at the individual, group, and system levels comes at a time when school districts nationally are pursuing personnel evaluation models that link teachers' instructional practices to student achievement. School psychologists have an opportunity to take a leadership role in determining how the impact of their service delivery will be evaluated. The purpose of this article is to: (a) describe the legislative context and historical trends for professional accountability for school psychologists; (b) provide four key principles to consider in designing an accountability system for school psychologists; (c) outline the advantages, disadvantages, and recommended guidelines for using case studies (i.e., single-case designs) and rubric-based approaches for evaluating school psychological services; (d) illustrate how case studies are used to demonstrate accountability in a state-wide school psychology internship program; and (e) discuss the implications for the graduate preparation of school psychologists. (Contains 1 table.)