This research aimed to study the use of instructional model based on CLT in teaching Thai reading comprehension to foreigners with Malaysian Siamese Students. The instructional model consisted of 4 activity stages: 1) attitude enhancement 2) learning content 3) presentation and 4) evaluation. The instruments were 1) 8 lesson plans 2) 30 items of reading comprehension test 3) 15 items of attitude scale on Thai reading and 4) 15 items of questionnaire on satisfaction. This research used one group pretest and post test design. The samples were 20 Malaysian Siamese students from Thai Language School at Thepchumnum (Naka) Temple. Mean, standard deviation and Wilcoxon signed ranks test were used in this research. The findings revealed that Malaysian Siamese students’ reading comprehension and attitude on Thai reading was significantly higher at the level of .01 after learning through the instructional model and the students’ satisfaction was significantly at the high level of .01 after learning through the model.