In the basis of learning a new language, lies the person's understanding of what s/he hears or reads and ability to express him/herself in that language well. Therefore it requires speakers have an extensive vocabulary to communicate with other people effectively, hence vocabulary has an essential position in learning a foreign language. In this research, the effect of context-based vocabulary teaching implementation in instruction of Turkish as a foreign language was studied and experimental and control groups of B2 grader participants were studied with. Experimental group had context-based vocabulary education while control group was given traditional education. This study is a mixed designed research in which quantitative examination methods were used in company. In qualitative studies, documental analyses were made on sentences that participants' predictions about word meaning were involved, and in quantitative version of the study experimental research was made. Pre-tests and post-tests were practiced on groups. Data of pre and post-tests that were made to compare the groups' vocabulary levels were analyzed with Mann Whitney-U Test, and to evaluate the alteration of both groups in themselves, Wilcoxon Signed Rank Test. It was observed that both of the groups were in close levels to each other at pre-test, and lexical gain of experimental group was far more bigger than control group at post-test. At the end of the research, it is deduced that context-based vocabulary teaching method is an effective way of vocabulary teaching in instruction of Turkish as a foreign language.