To examine the impact of cooperative learning strategy on the behaviour states of EFL learners, a 3-month study was conducted in 4 government secondary schools in EFL context (Saudi Arabia). This study aims to identify the effect of cooperative learning in comparison to traditional learning in learning English grammar on the behaviour states of EFL Learners. This study contributed to the knowledge about how EFL learners behave when they interact cooperatively together in cooperative learning groups in comparison to their colleagues who learn in traditional learning. In this study, the participants were 139 tenth grade male students, in 4 male government secondary schools in Al-Baha city, in Saudi Arabia context.An examination of the Kruskal‑Wallis tests shows that the EFL learners in the experimental conditions displayed more cooperative behavioural states and less non‑cooperative states, individual task‑oriented, and individual non‑task behaviours than their classmates in the control condition. In addition, outcome scores were, on average, higher in the experimental condition for cooperative behavioural outcomes. They were lower in the experimental condition for non‑cooperation behaviour, individual task oriented and individual non‑task oriented.