Liberal Studies (LS), a high-stakes senior secondary school subject in Hong Kong, has evoked widespread debate in recent years concerning the curriculum content about Mainland China. Highlighting the deregulated textbook policy on this subject as adopted by the Hong Kong Education Bureau (EDB), this paper compares how specific socio-political issues in Mainland China are depicted in government-published and commercially-published LS textbooks. The findings demonstrate a significant mismatch between government and commercial textbooks, as well as differing narratives about Mainland China from one commercial publication to another. The paper argues that these divergences are closely related to the EDB's current LS textbook policy, and they are reflective of the contradictions in the ongoing debate about LS and regional politics more broadly. Theoretically, this paper seeks to enrich the understanding of the notion of 'official knowledge' in critical curriculum theory, via an examination of the 'non-official' realm of knowledge production.