This research was a developmental research which was aimed at developing bilingual mathematics teaching-learning instruments based on STAD cooperative learning setting for grade X senior high school students. In this study the students' handbooks and teacher's instructional guides were developed following Plomp's developmental procedure which consists of five stages: (1) preliminary investigation, (2) design, (3) realization, (4) test, evaluation, and revision, and (5) implementation. In this study the implementation stage was not involved because of the research limitations. According to research findings the instruments which had been developed have good quality based on the consideration of three aspects: validity, practicality, and effectiveness. The validity score of students' handbook was 3,63 and the one of teacher's instructional guide was 3,77. These scores were in the range of 3,5≤Sr<4, showing that students' and teacher's handbooks were very valid. The practical aspect of instruments was analysed using teaching-learning observations, teacher's response and students' response. The observations average score of using those instrument in the first learning cycle was 3,29 which was in the range of 2,5≤Sr<3,5. This showed that the practical aspect of using instruments was in practise catagory. In the second and third cycles, the observations' average scores of the teaching learning process were 3,61 and 3,83 which both were in the range of 3,5≤Sr<4,0. These indicated that the practical aspect of instruments were very practicable. The score of teacher's response was 3,65 which was in the range of 3,5≤Sr<4,0. This indicates that the practical aspect of instruments was very practicable. The score of students' response was 3,44 which was in the range of 2,5≤Sr<3,5 showing that practical aspect of instruments was in practise catagory. Morever, instruments effectiveness was measured using students achievement in cognitive and affective domain. The score of students achievement in the cognitive domain in the first cycle was 83,2, the second cycle was 86,13, and in the third cycle was 88,83. The students score in affective domain was effective.