Further study is warranted to investigate the effect of PBL on students’ critical thinking in a longitudinal design. A continual exposure to PBL processes should also be effective in nurturing students’ critical thinking. The implication is that the PBL procedures used in this study might be useful for educators in polytechnic, with some modifications of the original framework. It is suggested that future research replicates the study and modifies the proposed PBL procedures to focus on the process of stimulating students’ meta-cognition, as well as increase students’ awareness of their critical thinking. These are in respect to the processing such as discussion, brainstorming session, debate session, interaction, reflection, feedback, and teaching each other. In this capacity, it is also important to identify which components in PBL process that are really effective in stimulating each of the variables of interest, such as critical thinking.