Researcher-implemented writing interventions have been shown to improve student writing performance. However, there has been limited research on teacher-implemented writing interventions, which are more likely to be sustainable in a classroom. The purpose of this review was to examine the effectiveness of teacher-implemented writing interventions in regular-classroom environments with elementary-aged students. The inclusion criteria resulted in the identification of 13 experimental research studies. Classroom teachers implemented a range of writing strategies. However, explicit strategy instruction, including self-regulated strategy development, was the most commonly used approach that improved students' writing achievement. Practical implications of the results are discussed and directions for future research are provided.