A growing number of governments, seeking to modernise their country's education system, adapt cooperative learning (CL) as a major component of their educational policy. Since the 1960s, when CL re-emerged to become a systematic pedagogy, CL practice has been constantly refined on the basis of ongoing research. Research results have consistently shown that CL improves students' academic achievement as well as social interaction when carried out responsibly. CL methods and procedures are designed to promote cooperation and mutual assistance among learners and often carry over to relationships outside the school. Translating the promise of CL to practice is more complicated than meets the eye, and does not always guarantee that its desired goals are achieved. This article sets out to explore some of the causes of the discrepancy between the promise and practice of CL, such as confusion about methods, lack of adequate preparation, and teachers' perceptions of teaching in general and of CL in particular.