The acquisition and use of academic vocabulary has a direct impact on educational outcomes for L2 students, in academic preparation programmes, undergraduate studies and postgraduate work. This study investigated the challenges of learning academic vocabulary among 16 postgraduate Saudi students who are studying in New Zealand universities. The study takes the position that students‟ perspectives of the challenges they face in acquiring academic vocabulary can offer an alternative perspective to existing research on academic vocabulary. The study asked four research questions: 1) In which aspects of postgraduate studies are the challenges of learning academic vocabulary mostly found? 2) What are the challenges that postgraduate Saudi students face in acquiring academic vocabulary? 3) What strategies do these postgraduate Saudi students use to learn academic vocabulary? and 4) Do students who report the most challenges tend to have the least vocabulary learning strategies? To answer these research questions a qualitative case study approach was adopted and data were collected through an initial survey, individual face-to-face interviews, and a focus group interview. The findings show that every one of the 16 participants struggled with academic vocabulary, variously in a number of academic settings and across all four language skills. Reading to write (Hirvela, 2016) was of particular challenge due to the extensive need to paraphrase from original texts. Additionally, the study found that participants had little prior knowledge of how to acquire academic vocabulary and had few learning strategies to address their difficulties. The findings of this study did not lead to a conclusion that simple exposure to academic vocabulary can increase the chance of incidental vocabulary acquisition but rather, on the contrary, suggests that purposeful vocabulary learning is needed and that such learning needs to be grounded in sound learning strategies, including the use of vocabulary learning tools. Moreover, the study revealed that inappropriate vocabulary learning strategies can cause frustration and loss of motivation. The study has implications for EAP preparation programmes in Saudi Arabia (and indeed elsewhere) and for postgraduate support in New Zealand universities.