Thailand's education has not succeeded in meeting the Ministry of Education Thailand's goals for Thai language. The problem manifests in students' substandard Thai reading comprehension. Results of the Thailand's standardized national test showed that students, especially those with economical disadvantages, have performed poorly in Thai reading comprehension for many consecutive years. A confounding factor could be the dearth of evidence-based comprehension instruction in Thai classrooms. This mixed methods study examined the effectiveness of Question-Answer Relationships, which is an evidence-based comprehension strategy, in a Thai reading classroom. Fifty-seven fifth graders and one teacher participated in the study. The quantitative research design was quasi-experimental, including both a control group and pre-post test design. Results showed evidence that the strategy helped the treatment group to significantly improve and outperform the control group in Thai reading comprehension tests. The qualitative research design employed case studies to examine the perspectives about reading comprehension of the treatment group versus the control group, and the teacher's perspectives before and after teaching Question-Answer Relationships. Qualitative findings yielded insights into the positive impact of the strategy on the treatment group's and the teacher's perspectives of reading comprehension. Because this study was the first to investigate Question-Answer Relationships in the Thai language, there is a need for continual future research to build an incremental amount of the strategy's evidence of success in Thai classrooms. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]