How do language and culture pose adjustment challenges that hinder the academic success of postgraduate international students? This article answers this question based on a thematic analysis of 55 semi-structured qualitative interviews conducted with postgraduate international students and academic and professional staff members at a Malaysian research-intensive public university. The results show that language and culture are influential in a range of academic (language, supervision, research training) and social (group work, friendship) adjustment challenges. The analysis highlights how these challenges hinder academic success as a result of limited or frustrated pathways for students' linguacultural development. We conclude that future academic research and university policy to support postgraduate international students may pay greater attention to cross-cultural, linguistic, and linguacultural issues.