This study aims to determine the effectiveness of mobile learning based android in learning vocabulary at the seventh-grade students of SMP Batara Gowa. This type of research is pre-experimental. The research design used was pre-experimental design, namely one group pre-test post-test design. The populations in this study were all seventh-grade students of SMP Batara Gowa, and the sample was class VII.1 as the experimental class which was chosen by using purposive sampling. The results of the data analysis show that the mean score of post-test (70.55) was higher than the mean score of pre-test (34.65). The result of the t-test was 30.117 and t-table 2.093. It could be indicated that the null hypothesis (H0) was rejected and the alternative hypothesis (H1) was accepted. Based on the effectiveness criteria, generally using mobile learning based android was effective in learning vocabulary at the seventh-grade students of SMP Batara Gowa.