Speaking is communication ability that in the process delivering and expressing ideas, thoughts, and feeling directly to people. In reality, there are many students still difficult to be able speak using English. Important factor that affect the students’ speaking ability is vocabulary. The purpose of this research is to investigate whether there is significant correlation between students’ vocabulary mastery and students’ speaking ability at the eleventh grade students of SMAN 1 Abung Selatan academic year 2022/2023. In this research, the researcher used correlational study. Population of this research was all of the eleventh grade students of SMAN 1 Abung Selatan that consist of 118 students. Sample of the research were 32 students. Sampling technique that is used was proportional random sampling. The instrument that is used were speaking test and mutiple choice test. To analyze the data the researcher used Pearson Product Moment formula and t-test. The result of analysis test was value of rcount was greater than value of rtable(0.884>0.349). It means that there is significant correlation between vocabulary mastery and the students’ speaking ability at the tenth grade students of SMAN 1 Abung Selatan in academic year 2022/2023.