Pair/group work activities are now common in classroom and it is one of the prominent features of the learner-centred approach. This study aimed to investigate (1) teachers' perceptions toward group work and (2) their group work implementations in EFL speaking classes. The data were collected via a questionnaire from 105 high school English teachers within Dong Thap province (one of the remote provinces in the Mekong Delta, South of Vietnam) and video-recordings taught by 4 teachers who had answered the questionnaire and agreed to permit the researchers to record their instructions at 4 different high schools in the province, where they were working full-time. The obtained results showed that most teachers highly appreciated the significance of group work in speaking classes. They generally understood clearly its benefits, possible problems and teacher roles in supporting groups for success and enjoyment. However, for greater effectiveness in group implementation, some suggestions are given.