Educational standardized testing impacts millions of children and educational professionals each year. In the current accountability climate, an effective educational system depends on professionals who are literate in assessment and can take the appropriate actions in response to test results. Measurement researchers should begin to focus more attention on how teachers use assessment results, what skills teachers possess, and what teachers believe they can do in working with test results. This study examined elementary teacher knowledge and self-efficacy in measurement concepts through a random sample of teachers in the state of Washington. Teachers had greater success with skills related to basic measurement concepts compared to using test scores for informed decisions. No relationship was found between years of teaching and measurement knowledge or self-efficacy. However, teachers showing interest in resources for communicating test results to parents had lower self-efficacy compared to teachers not interested in resources. (Contains 2 tables.)