Students' transition from high school to university is a journey from a simple world to a complex one, with academic, social, and ethnic cultural transitions simultaneously occurring. Intercultural competence (IC) plays a crucial role in facilitating these cultural transitions. The aim of the study is to explore how university students undergo academic, social, and ethnic cultural transitions, along with determining what IC dimensions university students develop to have smooth academic, social, and ethnic cultural transitions. We adopted the constructivist grounded theory approach to gather and code interview data from 55 undergraduate students. Moreover, we conceptualised the five dimensions of students' IC in managing the complex transition by combining a person-environmental interactive perspective. This was constructed with the widely acknowledged interpersonal communication perspective of IC. We found that students need to navigate multiple cultural transitions in different aspects and processes, and that IC plays an important role in easing them. The study results indicate that students should improve their IC from five aspects to facilitate their academic, social, and ethnic cultural transitions. Further, they must continuously introspect on themselves and the external world to nurture critical thinking in their academic and sociocultural life.