Agus Mulyana Dosen Pembimbing 1 Purnawati Dosen Pembimbing 2 Sri Lestari Ketua Penguji Nirna Nirmala Penguji 1 Lastry Forisa Penguji 1 Sekar Ayu Oktaviana Putri Pengarang

This research describes the use of authentic reading material to build students’ vocabulary and self-confidence. The purpose of this research is to find out whether there is an effect of self-confidence and vocabulary mastery at the eleventh grade of SMKN 8 Kabupaten Tangerang in academic year 2022/2023 after learning using authentic reading material. The sample used is 38 students. The writer used quantitative methods with quasi-experimental design one group pre-test and post-test. The research was done by conducting pre-test, treatment, and post-test. The result showed that the use of authentic reading material gives the effect to students’ self-confidence and vocabulary mastery. The result value of students’ self-confidence is 73.26%, which means that students’ self-confidence in the XI AK1 during the learning process is categorized as “good”. The result of vocabulary test was Ha accepted and Ho was rejected. It can be shown from T-test that sig. 0.000 < 0.05. It means that there is a significant difference between the pre-test and post-test at eleventh grade students of SMKN 8 Kabupaten Tangerang after being taught by using authentic reading material.