Much research has been done to explore social media on students and instructors and their perceptions of social media use in higher education, but little research has been done on teachers in secondary education and their perceptions of social media use in the classroom. Due to the lack of research, the purpose of the study was to examine teachers' perceptions of social media use to improve "students' learning" and "students' engagement" and if their perceptions varied by selected demographic variables. The study was conducted in three northeast Mississippi secondary schools, a 6th and 7th grade school, 8th and 9th grade school, and 10th-12th grade school, during the spring semester of 2021. A survey instrument, "Social Media Survey for Secondary Teachers," was used in the study. The study was completed by 53 participants (44 females and 9 males). The research design for this study was descriptive and causal comparative. The study found that teachers' perceptions of social media use for classroom instruction to improve "students' learning" and "students' engagement" was "neutral." Also, a statistically significant difference was found between teachers' current position (e.g., special education teachers and other teachers) and the use of social media in the classroom to improve "students' learning." However, there was no statistically significant difference found between teachers' perceptions of the use of social media in the classroom to improve students' engagement and the demographics: gender, age, race, teacher certification, years taught, years at current school, teachers' current position, number of subject(s) taught, years at current position, number of grade levels taught, and number of social media used. The findings of this study provide information for teachers, administrators, and school districts so they may determine if they will use social media. Further research is recommended using more school districts, which can provide more data for comparison and a better understanding of teachers' perceptions of social media use in the classroom for students' learning and students' engagement. In addition, further research should be done on teachers' current position and their perceptions of using social media to improve students' learning. [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.]