In order to enhance our students' thinking skills and improve their achievements, teachers have to be our targets for development and training. In this study, a self-constructed questionnaire was employed to investigate teachers' perceptions, practices and constraints of teaching thinking skills across Science and Mathematics curriculum. Purposeful and stratified random sampling techniques were used for selecting the female teachers of pilot and regular primary and middle schools in Medina. The findings indicated that the teachers have positive perceptions and they practice teaching thinking skills across the curriculum. However, the learning and teaching environment is not supporting them adequately towards the teaching thinking skills.