A quasi-experimental design was employed to evaluate the effectiveness of cooperative learning intervention. An experimental group and two control groups participated in the study. The cooperative learning fluency instruction was used in the experimental group while the traditional fluency instruction was use in the control groups. The author analyzed the data by using a one way analysis of covariance to test the differences between the experimental and control groups on post-test scores. The analysis of the data indicated that there was a significant difference between the experimental and control groups on means of reading fluency (F (2, 65) = 28.884, p = 000, partial η2 = .47). The findings revealed that the cooperative learning fluency intervention had positive effects on reading fluency for students in the experimental group. The implication can be drawn from these findings that cooperative learning can be effectively used in Turkish elementary classrooms to improve students’ reading fluency and overall reading proficiency.