This study aimed at: 1) investigating what kinds of authentic materials are used  by the  English  teacher  of  SMP  Al-Islam  1  Surakarta;  2)  exploring  the reading activities that could be done using authentic material; 3) identifying the reading indicators that can be improved by using authentic material; 4) investigating the factors that influence teacher’s decision in using authentic material as reading supplementary materials; and 5) identifying teachers’ role in the use of authentic material in teaching reading.

This study applied qualitative case study design conducted at SMP Al- Islam 1 Surakarta. The subjects of this study were chosen through purposive sampling, i.e. an English teacher and some eighth grade students of SMP Al-Islam 1 Surakarta. The data of this study were obtained from observation, interview, and documents analysis. Meanwhile, the analysis technique was adopted from the “bottom-up” approach designed by Creswell.

The findings of this study are:  1) The authentic materials used by the eighth grade teacher of Al-Islam Junior High School are texts obtained from the internet, printed story book, videos, and pictures; 2) The reading activities conducted by the eighth grade teacher of Al-Islam Junior High School through the use of authentic materials as supplementary materials are reading aloud, walking gallery,  filling  in  blanks,  rearranging  jumbled  paragraphs,  doing  cloze  tasks, having short answer tasks, conducting information transfer, having text analysis, and doing some vocabulary ordering; 3) Through the use of authentic materials, students’ vocabulary mastery and ability in understanding reading text improve; 4) The reasons for using authentic materials are demotivated students and unappealing English text book material, and also to create lively atmosphere in the classroom; and 5) The teacher’s roles in the use of authentic materials in reading lessons are as a manager and a resource provider. The result of this study shows that authentic materials can help the teacher design various lively reading activities. Besides, the result of the study also indicates that students’ vocabulary and text understanding can be improved through the use authentic materials in teaching reading.