An increasing number of students at the University of Brunei Darussalam are studying the Japanese language. However, research on the relationship between learners' motivation and their achievement has not been given sufficient attention in Japanese foreign language education compared to English in Brunei. The present study, which utilized a quantitative survey, attempted to address this information gap. Based on the Brunei university student sample, five main motivational factors were extracted by factor analysis, namely: (1) Interest in Japanese pop culture and traditional culture; (2) Interest in Japanese language orientation; (3) Understanding Japanese people and society orientation; (4) Career use of Japanese language orientation; and (5) Self-satisfaction orientation. Participants differed significantly in their Japanese language learning motivation by gender and age. Male students were more driven to study Japanese language by Factor 1-Interest in Japanese pop culture and traditional culture orientation while females were inspired mostly by Factor 5-Self-satisfaction Orientation. In addition, students placed in the oldest age-group category (24-27) scored significantly higher on Factor 3-Understanding Japanese people and society orientation, than members of the other two age-groups. Based on these findings, nine recommendations were made to improve the teaching and learning of Japanese language at the university. Further mixed-methods research was also recommended to gain additional insights.