Abstract: This article reports the results of an experimental investigation of the effect of a new type of cooperative learning technique, named Interest-Oriented Student Team Achievement Divisions (IOSTAD) by the researchers of the present study, on the students’ reading comprehension achievement of English as a foreign language (EFL).In so doing, two classes (n=25) were assigned to control and experimental conditions. Each class was divided into four groups of three. The control group was instructed via Student Team Achievement Divisions (STAD) technique, which is a well-known technique of cooperative learning, while the experimental group followed the same technique plus adding students’ interest in their grouping and cooperation i.e., IOSTAD technique. It was assumed that considering students’ interest in their grouping and working together would lead to better performance in reading. Two different domainreferenced multiple-choice reading comprehension tests were used to assess the reading comprehension ability of the students on a pretest and posttest. The results on an independent T-test showed statistical significance at P≤0.05 level that can be attributed to the effect of adding students’ interest in cooperative learning on their reading comprehension achievement.