This study aims to examine the effectiveness of semantic mapping strategy in developing the vocabulary skills for grade nine female students in the basic education in Oman. The researcher designed a manual for teachers on how to use the semantic mapping and vocabulary skills test. The Manual and the test were evaluated by a number of specialists. The test internal consistency was checked using Cronbach Alpha Coefficient which scored (0.81). The sample of the study was divided into two groups; an experimental group of 27 female students, who were taught using the semantic mapping strategy during the reading and literature classes, and a control group of 31 female students, who were taught with the conventional teaching method. Post the experiment, both groups were given the vocabulary skills test. The results show a statistical significance difference at (a <0.05) between the means of scores of the two groups. The difference was in favor of the test group which can be attributed to the teaching method. Based on the study results, the researcher recommends focusing on developing vocabulary skills by using different strategies such as the read-aloud strategy, the key words strategy and so on. Moreover, the researcher recommends using the semantic mapping strategy in teaching different aspects of Arabic language such as reading comprehension, vocabulary, critical reading, writing etc.