Integrating content and language at tertiary level has recently become very popular in Asian contexts. Extensive studies have also been done, evidencing that CLIL (Content and Language Integrated Learning) can be beneficial for improving learners’ linguistic outcomes and content achievements. However, cultural awareness, as one core dimension of the 4Cs (communication, content, cognition, and culture) conceptual framework is less addressed in the literature. Often it is assumed that CLIL education can also naturally increase learners’ cross-cultural competence, but hard evidence on the increment of this competence is still lacking in the CLIL literature. Thus, to bridge this gap, the present study used a mixed research method to investigate to what extent a self-produced CLIL culture coursebook can help university students enhance their inter-cultural knowledge in a national Taiwan polytechnic university. One survey was conducted to evaluate the tailor-made CLIL materials and another was administered to measure the cultural competence after the CLIL intervention. The coursebook writers as well as the CLIL learners were also interviewed in the study. The findings showed that the contextualised design met its set educational aims and targets, and the users made significant improvement in their cultural competence. Also, the interviewees showed a high degree of satisfaction with the coursebook and the approach, although the book authors held divided opinions on some issues. Implications and suggestions are provided.