The present study studied the role of teaching methods and learning styles in the effectiveness of second language teaching. This study was applied in terms of its purpose and survey in terms of its method, and studied 384 male students of the second year of high school in Tehran in the academic year 1403-1404 as an available sample. In collecting data on the variable of teaching methods (including the components of specialist, official position, personal model, facilitator and delegate), the Giroux Teaching Methods Questionnaire (1994) was used. In collecting data on the variable of learning styles (including the components of exploratory style, group style, experimental style, structured style and observational style), the Towler & Dipboye Learning Styles Questionnaire (2003) was used. For the variable of effectiveness of second language teaching, the English course grades included in the students' first semester report cards in the academic year 1403-1404 were used. Structural equation modeling, Sobel test, and Smart PLS ver3 software were used to analyze the data. The results of the study indicate that teaching methods and learning styles play a significant role in the effectiveness of second language teaching. Also, learning styles play a mediating role in this model. Therefore, teachers can create harmony and compatibility between their teaching methods and students' learning styles by adopting flexible approaches in education, in order to increase the effectiveness of second language teaching and the level of student learning.