ABSTRACT Novita Ngabito. 2023. Developing supplementary English reading material for grade X of agriculture vocational high school. English Education Department, Postgraduate Program, Gorontalo State University. Advisors: Prof. Dr. Hj. Moon H. Otoluwa, M.Hum and Dr. Rasuna R. Talib, M.Hum. The main problems of this study were “What are students of Vocational High School of Agriculture study program need in learning English? And “How is the development of supplementary English materials for reading skill?”. The objective was aimed to describe the development of supplementary reading material for tenth grade vocational high school based on curriculum 2013. The subject was the agriculture students grade X in 2022/2023 academic year which consists of sixteen students. This research used research and development (R&D) method. This research was conducted by following ADDIE models with some modification. The first step was conducting a needs analysis by distributing a questionnaire to the students. The results of the needs analysis were used to develop the syllabus. The syllabus was the guideline to develop the first draft of the materials. Then, the first draft was evaluated by a learning materials expert. The results of the materials evaluation were then analyzed through descriptive statistics and used to revise the first draft of the materials. The product of this study is four units of English reading materials. Each unit divided into five stages proposed by Crawford (2003) such as relating, experiencing, applying, cooperating and transferring. The finding of the study are describe as follow (1) the students need to get an English learning in order to be able to get information through English reading text. (2) the learning need of student is the learning material for reading of which topics are related to agriculture related on their study program. (3) the English book developed as the product of this research is appropriate based on the result of expert judgment, readability. (4) The English book developed offered an influence on students’ skill in reading. Finally it can be concluded that the English reading material based on contextual teaching and learning was appropriate for X grade agriculture study program in vocational high school. Keywords: English supplementary materials, English Reading for Agriculture, material development