This study investigates the impact that study in Australia has on the lexical knowledge of Saudi Arabian students. It focuses on: 1) the effects that the length of study in Australia has on the acquisition of lexical collocations, as reflected by lexical knowledge tests, and 2) whether there is a significant gender difference in the acquisition of lexical collocation knowledge. The results indicate that there is a positive correlation between the length of stay in Australia and the knowledge of lexical collocation, since the overall mean scores of the entire sample increased with the number of the years spent in Australia. Participants who stayed for one year had the lowest mean score of 7.39, whereas those with the longest length of stay of four years had the highest mean score of 8.76. Participants staying for two or three years had minimal improvements, with mean scores of 7.64 and 7.68 respectively. The results indicate that there was only a slight difference between male and female participants in their knowledge of lexical collocations, with overall mean scores of 7.56 and 8.35 out of 12 respectively.