Critical thinking is an important life skill that needs to be nurtured in young minds during the primary education years. This study explored pre-service teachers' perception of barriers to their efforts in promoting critical thinking skills in classrooms, and further explored possible solutions to overcome these perceived barriers. The study used an exploratory mixed-method research design. Data were collected through an online survey and subsequently a focus group discussion to explore further the results of the quantitative data. Twenty-two pre-service teachers responded to the online survey, and subsequently seven pre-service teachers were selected for the focus group discussion. Issues related to teacher preparedness to assess pupils' critical thinking skills, inadequate background knowledge on critical thinking, and lack of appropriate resources emerged as barriers to promoting the development of critical thinking skills in classrooms. The study suggests changes in teaching methods courses offered in teacher preparatory programs and changing perceptions toward critical thinking skills as possible measures to promote the development of critical thinking skills in the classroom.