The Literacy Orientation Survey (LOS) is an instrument for assessing teachers' beliefs about literacy learning and classroom practices. It was constructed in stages designed to measure the construct of literacy beliefs and practices in constructivist classrooms. Content validity of the LOS was established by a panel of experts who reviewed the items, judging how well items reflected principles of constructivist approaches to literacy instruction. A draft survey of 44 items was administered to 110 teachers. After factor analysis of responses, 30 items, 15 belief statements and 15 practices statements, were retained. The resulting LOS survey was administered to 30 different teachers in order to determine the reliability of the instrument. The LOS was subsequently administered to 95 teachers. While the LOS was determined to have robust internal validity and reliability, questions remained about external validity of teachers' self-reports of their approaches to instruction. To assess external validity, 42 teachers were observed during actual classroom instruction. They were categorized as traditional, eclectic, or constructivist based on indicators used during the observations. The LOS was then administered to these same 42 teachers. LOS scores, by teaching category, were compared using Analysis of Variance. Homogeneity of variance across groups was assured (Levene Test). The conclusion was reached that the LOS consistently predicted actual classroom practice and that it can be used as a reliable and valid indicator of teachers' practices during literacy instruction. The LOS is attached. (Contains 48 references.) (Author/ND)