A random sample of language arts, social studies, science, and math high school teachers from across the United States were surveyed about their use of writing to support student learning. Four out of every five teachers reported they used writing to support student learning, applying on average 24 different writing activities across the school year, with nine activities applied by at least one-half of the teachers once a month or more often. Teachers' responses, however, raised several concerns. One, a majority of teachers indicted they did not receive adequate preservice or inservice preparation on how to use writing to support learning (this issue was especially acute for science and math teachers). Two, many of the nine most commonly applied writing to learn activities involved little or no analysis, interpretation, or personalization of information to be learned. Three, use of writing activities involving the use of digital tools, report writing, and written arguments were infrequent. Such activities are stressed by the Common Core State Standards. Four, when respondents taught students how to apply writing to learn activities, they only used effective teaching practices slightly more than one half of the time (math teachers did this even less often). We further found that use of writing to support learning was related to teachers' preparation to apply such strategies, perceptions of capabilities to teach and use these tools, and percent of below average students in the class.