Inspired by the rise of Communicative Language Teaching, some scholars have vehemently rejected any use of L1 in L2 learning classes (e.g., Atkinson, 1987) while others have advocated the use of L1 as an efficient tool to facilitate communication (e.g., Nation, 2003). However, caution has been raised against the excessive use of L1 (Nation, 2001). This study was conducted to observe classroom dynamics in terms of the quantity of use of L1 in two randomly-selected pre-university English classes in Ahvaz, Iran. The objective was to seek both students and teachers' perceptions and attitudes towards the use of L1 in L2 classes. The classes were observed and video-taped for 6 sessions and the teachers and four high-achieving/low-achieving students were interviewed. The findings showed that an excessive use of Persian could have a de-motivating effect on students. Hence, the interviewed students voiced dissatisfaction with the untimely use and domination of L1 in L2 classes.