Abstract The aim of the study was to investigate effects of comprehensible input on students‟ speech fluency and accuracy at Assosa primary school (Grade 8 students). The design of the study was quasi experiment. For the study, hundred (100) grade eight (8) students were selected using convenient sampling technique and the researcher provided them oral pretest and posttest. To group these students (Room A & Room B) into experimental group and control group, the researcher used lotto method after oral pretest was administered. For experimental group comprehensible input was administered in the form of dialogue and debate while the control group students were taught using the usual teaching method in their natural classroom for five weeks consequently. After all, the researcher analyzed the findings of experimental and control group students‟ speech fluency and accuracy using paired sample T test and independent sample T test. The findings of the study showed that students‟ speech fluency and accuracy were improved using comprehensible input (CI) than using usual teaching method which teachers used in the school. With respect to experimental group students‟ speech fluency and accuracy, a significance change was found. The experimental group students‟ speech fluency and accuracy were improved after intervention using comprehensible input (CI). That means, the influence of CI on students‟ speech had positive effect. At the end, recommendations were forwarded based on the major findings so as to minimize problems encountered and maximize the implementation of CI on speech fluency and accuracy. iii