The transfer of learning means that people apply knowledge and skills they have learned to new contexts. In this study, I investigated the importance of awareness of common principles and/or structures between previously learned content and transfer tasks in junior secondary school students. To conduct the research, I categorized the contexts for transfer into three different types based on the framework of Simons (1990, 1999): within a unit, new learning, and daily life. The results showed that generally, the transfer of previously learned content was difficult, and many students struggled to transfer the content to new learning and  daily life in particular. Additionally, students who found a common principle between the previously learned contents and transfer tasks tended to correctly answer the transfer tasks. However, it became clear that even when students correctly understood the content they had previously learned, the content of the transfer task had an impact on whether or not they  were aware that their knowledge could be used for the transfer task.