The purpose of this study was to find out whether Padlet application media was effective in increasing students' vocabulary mastery. This research was conducted at SMA Negeri 1 Kejobong Purbalingga for the academic year 2023/2024 using a quantitative method and a pre-experimental design. In this study, classes X-A and X-B were used for try-out classes and experimental classes with 35 and 36 students in each class. Try-outs have been carried out in class X-A to calculate the validity of the questions that will be given to class X-B as an experimental class. The experimental class was given a validated test in the form of a pre-test and post-test. The pre-test was given before the treatment and the post-test was given after the treatment. The pre-test and post-test data will be analyzed using SPSS 26. The results of the pre-test are 55.88 and the post-test are 75.44 which indicate a significant change. The results of the analysis show that sig (2-tailed) is 0.000<0.05 which means that H0 is rejected and H1 is accepted. It was concluded that the use of Padlet application media was effective in increasing vocabulary mastery.

Keywords: Vocabulary mastery, Padlet application media