OBJECTIVE To determine the variation in caesarean section rates among immigrant populations. BACKGROUND Australia is one of the most multicultural in the world and is also among those with the highest caesarean section rates. METHODS Secondary data analysis. METHODS Routinely collected data from a Local Heath District between 2011 and 2015 were analysed. Women were categorized into regional groups based on country of birth. Obstetrical risk was classified using the Robson classification. RESULTS In total 48 711 women gave birth, of whom 64.0% were born overseas; 13 966 had a caesarean section (28.7%). South and Central Asia women had a high number of caesarean sections (n = 4139; 29.6% of all caesarean sections), a high overall adjusted caesarean section rate (31.4%; 95% CI, 30.5%-32.3%), and consistently high caesarean section rates among women with single cephalic term pregnancy without a previous caesarean section. High adjusted caesarean section rates were seen among South East Asia women with nulliparous, single cephalic, term pregnancy, and spontaneous labour. Demographic and clinical characteristics explained 83.5% of the variation in overall caesarean section rates between country of birth and 21.8% to 100% depending on Robson group. CONCLUSIONS Caesarean section rates varied by country of birth and within some Robson groups. The studied factors had various effects on the variation in caesarean section rates between country of birth and Robson groups.