The purpose of this study is to recognise the effect of context on learning new vocabulary in an EFL college reading course and how contextualized vocabulary presentation could help in developing the mental lexicon in EFL readers. The research method followed in this study is quasi-experimental, involving a pretest-post-test control group design. Sixty EFL college students were chosen by convenience to participate in this study. Using a standardised vocabulary test and a vocabulary development intervention derived from the caveats of the natural approach and involving a five-phase instructional paradigm, the experimental group performance on the vocabulary test was compared to a traditionally taught control group. Findings showed that both groups were nearly homogeneous on pretesting. The results also indicated that the experimental group participants outperformed the control group in vocabulary learning on post testing as they improved from pretesting to post testing. Conclusions and implications for research were given in the end