The aim of the research was to improve the students‟ vocabulary in
English teaching learning process through Authentic Material. The subject of this
research was VIIB at SMP N 2 Kembaran in Academic Year 2015/2016. The
research used Classroom Action design. This action research was conducted in
two cycles. Each cycle consisted of planning, acting, observing, and reflecting. In
collecting the data, the researcher used observation, questionnaire, and objective
test consisted of pre-test and post-test. The result showed that the average of the
students‟ vocabulary in pre-test was 56.51%, in post-test 1 was 75.32% and in
post-test 2 was 86.19%. The observation result showed that the average of the
students‟ activity was 29.67% in cycle 1 and 47.08% in cycle 2. The questionnaire
result showed positive response towards the implementation of Authentic Material
for teaching vocabulary. The entire indicator had positive response from the
students. The highest percentage was 53.55% and the lowest was 0.32%. In
conclusion, it can be said that Authentic Material can be used to increase the
students‟ vocabulary mastery.