A random sample of language arts, social studies, and science high school teachers (N = 361; 53% women) from the United States were surveyed about what their students wrote, their use of evidence-based writing practices, the adaptations they made for weaker writers, how they assessed writing, their preparation to teach writing, beliefs about the importance of writing, and judgments about their students' writing capabilities. The findings from this survey raised some concerns about the quality of high school writing instruction. The writing activities they were assigned most frequently by teachers involved little analysis and interpretation, and almost one half of the participating teachers did not assign at least one multiparagraph writing assignment monthly. Although the majority of high school teachers did apply most of the evidence-based practices and adaptations included in the survey, they used these practices infrequently. Most teachers did not believe their college teacher education program adequately prepared them to teach writing. A sizable minority of language arts and social studies teachers indicated that their in-service preparation was inadequate too. For science teachers this was close to 60%. (Contains 7 tables.)