One of the most problematic areas for foreign language learning is collocation. It is often seen as arbitrary and overwhelming, a seemingly insurmountable obstacle to the attainment of native like fluency. The aim of this study is to increase awareness of the importance of teaching collocations in ESL/EFL classrooms in order for learners to acquire accurate and native-like competence. This paper is divided into four main sections. The first section discusses the definitions and categorizations of collocation from different scholars' perspectives as well as the distinction between collocation and other combinations of words. In the second section, the main sources of collocational errors will be clarified. The third section deals with the importance of collocations in ESL/EFL classrooms. In the fourth section different methodologies and materials for teaching collocations to ESL/ EFL learners will be suggested, as well as the implications of the lexical approach will be analyzed.