Breast cancer screening disparities continue to prevail with immigrant women being at the forefront of the under screened population. There is a paucity of knowledge about the role of religious affiliation or cultural orientation on immigrant women's cancer screening uptake. This study examined differences in uptake of breast cancer screening among women from Muslim and non-Muslim majority countries in Ontario, Canada. A cohort of 1,851,834 screening-eligible women living in Ontario during April 1, 2013 to March 31, 2015 was created using linked health and social administrative databases. The study found that being born in a Muslim majority country was associated with lower breast cancer screening uptake after adjusting for region of origin, neighbourhood income, and primary care-related factors. However, screening uptake in Muslim majority countries varied by world region with the greatest differences found in Sub-Saharan Africa and South Asia. Screening uptake was lower for women who had no primary care provider, were in a traditional fee-for service model of primary care, had a male physician, had an internationally trained physician, resided in a low income neighbourhood, and entered Canada under the family class of immigration. Religion may play a role in screening uptake, however, the variation in rates by regions of origin, immigration class, and access to primary care providers alludes to confluence of socio-demographic, cultural beliefs and practices, immigration trajectories and system level factors. Facilitating access for immigrant women to regular primary care providers, particularly female providers and enrollment in primary care models could enhance screening uptake.