Shortly after the political handover from Britain to China, mother tongue education was enforced in Hong Kong, which mandated the majority of the local secondary schools to switch the medium of instruction (MoI) from English to Chinese. Henceforth, schools were divided into Chinese-medium and English-medium. In 2001, a study was conducted to examine the attitudes of these two groups of students toward the three official spoken languages used in Hong Kong after the change of sovereignty (i.e., Cantonese, English, and Putonghua). Eight years later, a similar study was reconducted to trace the changes of students' perceptions upon relaxation of the mother tongue education policy. This article reports on a comparison between the two studies, through which the impacts of MoI policies on students' language attitudes were explored.