Reading strategies have been documented as beneficial facilitators for readers to understand text; their potential efficacy, however, has not yet adequately assessed among struggling readers in the context of a large number of students below grade level at secondary schools internationally. Using a pretest-posttest control group experimental design, the present study examined the effects of Chinese reading strategy instruction among struggling readers in grades 7 and 8 in mainland China. A sample of 342 struggling readers from five Chinese secondary schools participated in the intervention study. Students in the experimental condition received explicit teaching of reading strategies, whereas those in the control condition took regular classes. Results showed that the students in the experimental classes significantly outperformed those in the control classes not only in reading comprehension but also in autonomous reading motivation (ARM) and metacognitive awareness of reading strategies (MARS). No significant effects could be found on their controlled reading motivation. Furthermore, ARM and MARS partially mediated the effects of this instruction on reading comprehension. The findings imply that reading strategy instruction can be an effective approach to help struggling readers to improve their reading performance, with ARM and MARS acting as mediators.