The study on the effect of non-verbal communication on the effectiveness of classroom teaching was conducted at the Institute of Accountancy Arusha main campus. The study used a sample of 100 respondents who were selected randomly from BTCA students in the communication skills module at the Institute of Accountancy Arusha. The study used an explanatory sequential design that allowed the combination of quantitative and qualitative techniques in two phases, Quantitative data were collected through questionnaires, while qualitative data were collected through interviews. Validity and reliability were tested by using Cronbach alpha and content validity index respectively. These tests yielded 0.79 and 0.85 respectively indicating that the tools and their findings were reliable and valid. Data analysis was done by using simple linear regression and content analysis for quantitative and qualitative data respectively. The study found that there is a significant moderate positive relationship between the use of non-verbal communication on the effectiveness of classroom teaching. This study has found that effective use of non-verbal communication in classroom teaching leads to effective classroom teaching. Furthermore, the study has found that some students are not aware of the use of non-verbal communication signs. Also, it was found that some teachers use irrelevant non-verbal communication. The current study recommends that teachers should use non-verbal communication effectively but students must be trained on the usefulness of non-verbal communication in learning. Furthermore, there is a need for teachers to use relevant non-verbal communication signs in teaching as respondents said that there are signs that are considered to be non-verbal communication but when teachers use them students never understand them.