BackgroundAlthough feedback is consistently shown to have a positive effect on student achievement, there is also large heterogeneity in effect based on a variety of factors including how teachers use it in the classroom. Understanding how teachers use feedback as part of their content area literacy instruction in inclusive middle school social studies classrooms is therefore a worthy object of investigation. AimsThis paper applies an explanatory-sequential mixed-methods design to an existing dataset. We leverage this dataset to first understand whether teachers' feedback use improved students' ability to read social studies texts with understanding and acquire social studies content knowledge from text. It then characterizes the feedback teachers used and draws conclusions on how feedback's form may have influenced its effect. SamplesQuantitative analysis included 8865 min of audio recorded classroom instruction from 28 teachers in the United States. Additionally, social studies knowledge acquisition and reading comprehension achievement measures were collected from 893 students. Qualitative analysis included 37 transcripts of audio recorded lessons (38–65 min each) from five randomly selected teachers. MethodsQuantitative analysis preceded qualitative. Quantitative analyses included coding of all 8865 min to determine presence of feedback found effective by Hattie and Timperley (2007). This coding was used in a fixed effects model to investigate the effect teacher feedback use had on student reading comprehension and knowledge acquisition outcomes. Qualitative analysis included a collective case study of patterns of feedback use. ResultsFeedback did not have a substantial association with scores on the content knowledge or reading comprehension measures. Teachers’ feedback patterns suggest they frequently missed opportunities to help students understand goals and self-regulate their behavior as they moved toward them. ConclusionsThe ineffective forms of feedback displayed by teachers likely reduced feedback's effect on student outcomes.