This research aimed to study the teaching behaviors of the teaching Islamic studies pre-service teachers to encourage the students’ critical thinking skills and related conditions of the teaching behaviors to encourage critical thinking skills. Group discussion and the in-depth interview with the semi-structured questions were used in this qualitative study. Eleven Islamic studies pre-service teachers were selected by the purposive sampling technique with the criteria from three universities in the southern border provinces. The study revealed that teaching behaviors to encourage students’ critical thinking skills could be classified into three main categories namely 1) teaching behaviors, including; illustrating the interesting situation examples and request student’s suggestion prior the lesson; practicing the questions along with the content to inquire a reason from students; encouraging the students to analyze their learning problems and to develop the learning media to solve the problem by themselves; listening and offering various problem solutions to students; supporting the students for group knowledge sharing and discussion; 2) organizational behaviors, including; supporting and assisting the students in the out of class learning; creating the classroom environment to stimulate the thinking process, lastly, organizing additional thinking activities after class; 3) socio-emotional behaviors, including; teachers' self and emotional regulation; and considering the student nature and background. Thus, there were two categories of the conditions related to the teaching behaviors namely, internal conditions including; teacher self-learning; teacher characteristics; gaining knowledge from the classroom courses; seminar experience during the student teaching practice; teaching practice experience; and teaching with the understanding of student differences. Moreover, external conditions including; the university supervisor; the mentor teacher; the school training on the teaching in the 21st century; and the school and the community environment.