This quasi-experimental study aimed to investigate the effectiveness of applying cognitive linguistics (CL) to teaching English prepositions. The pretest-posttest between-group design was adopted. The participants were selected according to their previous learning experiences, regular out-of-class exposure, eagerness for joining the study, and pretest results. The spatial and metaphorical meanings of the prepositions above, among, at, behind, beside, between, in, in front of, on and under were taught in 4 sessions of 90 minutes. The Cognitive Group received CL-based instructions and the Traditional Group received instructions based on vivid pictures and verbal explanations. The findings showed that the Cognitive Group outperformed the Traditional Group in the posttest in terms of both the spatial and metaphorical meanings. It can be said that CL-based instruction can help learners improve their knowledge of the prepositions better than the traditional pedagogical application. It is recommended that applying cognitive linguistics can help students of other languages master English prepositions. The participants' responses to the questionnaires also assured research reliability and validity.