摘要:Vocabulary is the main building block of language learning which acts as the kernel for all language skills. The present study attempts to investigate the effect of applying SSOS on Iranian upper-intermediate EFL learners’ vocabulary learning. Lack of English vocabulary knowledge of Iranian learners as EFL learners encounters them with a lot of English using difficulties which influence their language abilities (reading, writing, listening and speaking). To this end, based on convenience non-random sampling selection, 40 upper-intermediate female learners were selected via Quick Placement Test. The participants were assigned to experimental (n = 20) and control (n = 20) groups. A vocabulary test as a pretest and a posttest were administered to all participants. The data were analyzed through descriptive and inferential statistics using SPSS software. The result of findings indicated that it is helpful to utilize SSOS as a tool to enhance not only learners’ conceptual and comprehensible processes in order to discover, guess and grasp the meaning of vocabulary but also to store and internalize them in their minds more successfully.