To identify the main factors that affect the quality of teaching in multi-grade elementary school classrooms a set of 61 research reports published between 2008-2021 was initially selected and then, upon further scrutiny, reduced to 18 for the final perusal and deductive content analysis. The results of this analysis show that teacher-related factors affect the quality of teaching more than the background factors and policy factors. Teacher-related factors include, but not limited to, classroom management, technological expertise, valid evaluation, academic specialization, and active teaching, while the background factors refer to things like facilities and equipment, grade composition, psychological environment, and dynamism of classroom and school atmosphere. Textbooks content, class time, cultural conditions, and further possibility of teachers delegating their responsibilities are among policy factors that affect the quality of multi-grade teaching in elementary schools.