Although researchers have made progress in understanding how discrimination affects health outcomes, challenges remain in efforts to analyze the distribution of discrimination-linked stress as a population-level risk factor. Discrimination often does not align with categorical comparisons but is racialized in practice. This study explicitly tests the effects of such racialized discrimination by using the increase in anti-Muslim discrimination following the attacks of September 11, 2001 as a natural experiment. Sociological scholarship suggests anti-Muslim discrimination has been racialized in a way that affects a variety of Middle Eastern and South Asian populations who are often targeted based on physical appearance, rather than religious identification. Using a name-matching algorithm to classify mothers based on name characteristics, I examine birth outcomes for mothers with ancestry from the Middle East and North Africa, South Asia, and a subset of South Asian Sikhs. I find that rates of low birth weight births increased for both Middle Eastern and North African (1.15 RR, 95% CI: 1.00- 1.31) and South Asian Sikh (1.61 RR, 95% CI: 1.06-2.40) mothers in the 37 weeks following September 11, relative to the same period one year prior. The results highlight how processes of racialization can distribute discrimination-linked stress as a risk factor in ways that are overlooked when relying on institutionalized racial, ethnic, or religious categories to study disparities., • Scholarship suggests Muslim racialization affects a variety of populations based on physical appearance, rather than religious identification. • This study tests the effects of racialized discrimination using anti-Muslim discrimination after 9/11 as a natural experiment. • This study uses name characteristics to identify Middle Eastern, South Asian, and Sikh mothers in California. • LBW births increased for MENA and Sikh mothers following September 11, but not the broader population of South Asian mothers. • Racialization distributes discrimination and stress in ways overlooked by single categories of race, ethnicity, or religion.