Given the frequency with which teachers use self-developed tests to evaluate students, and given the paucity of requirements related to developing measurement competencies, some educators and measurement specialists question the adequacy of teachers' training in and knowledge of measurement principles. This study assesses teachers' measurement training and the extent to which their measurement knowledge is adequate to develop quality classroom tests. Forty-one 7th- and 8th-grade science and mathematics teachers were assessed using a 65-item multiple-choice test and an interview protocol. Participants were asked to identify violations of item writing principles in 32 multiple-choice and completion items. Three questions were addressed: (1) What was the nature and extent of measurement training? (2) What measurement knowledge and skills did these teachers possess? and (3) What teacher characteristics are related to their measurement knowledge? Results indicated that teachers' knowledge of measurement was insufficient, probably at least partially due to inadequate training; and that teachers frequently tested students with their own tests and placed more weight on students' scores on these tests when assigning end-of-course grades than on other forms of assessment. (LL)