In multicultural societies such as Australia, examining the potential similarities and differences of students' motivational profiles cross-culturally is an important topic for research. For the most part, goal theory research has been conducted using Caucasian samples and the potential differences between cultural groups have remained relatively unexplored until recently (Urdan & Giancarlo, 2000). The purpose of the current research was to explore cross-cultural similarities and differences in the motivational profiles of Indigenous Papua New Guinean (PNG) and Indigenous and non-Indigenous Australian students. A total of 1792 secondary students, across the three cultures, completed self-report motivational measures. Invariance testing demonstrated that the Inventory of School Motivation (ISM - McInerney, Yeung & McInerney, 2001) measure was invariant across cultural groups. The current findings highlight the strength of the ISM and the importance of assessing invariance testing over diverse cultural groups.