Purpose: The purpose of this study was to examine the effect of perceived social support on postpartum depression (PPD) in Arab immigrant mothers and Turkish mothers. Design/methodology/approach: This descriptive study was conducted with 140 mothers between September 2017 and January 2018. The data was collected via the Turkish and Arabic versions of the sociodemographic questionnaire, the Edinburgh Postnatal Depression Scale (EPDS) and the Multidimensional Scale of Perceived Social Support. Percentage and arithmetic mean calculations, independent samples t-test, Mann–Whitney U test, paired logistic regression analysis backward elimination method and Pearson and Spearman correlation analyses were conducted to analyze the data. Findings: The data revealed that the risk of PPD was twice as high in Arab immigrant mothers (56.3%) compared to Turkish mothers (29%). The EPDS mean score was 12.37 ± 6.28 for Arab immigrant mothers and 8.81 ± 5.48 for Turkish mothers. The social support mean score was found to be 50.70 ± 19.27 for Arab immigrant mothers and 61.41 ± 16.51 for Turkish mothers. The independent risk factors for Turkish mothers included mother’s age, monthly income level and infant’s age, while the independent risk factors for Arab immigrant mothers included number of children, husband’s status of employment and access to regular medical care during pregnancy. The negative correlation between EPDS and social support overall scores and subscale scores was found to be significant for both groups. Originality/value: To the best of the authors’ knowledge, this is the first study on the impact of social support on PPD in Arab immigrant and Turkish women in the national and international literature. The study helped reveal the correlation between perceived social support and PPD, the PPD risk rates and risk factors according to citizenship status for the first time.