Objective <p>This study aimed to estimate (1) rates of SUID and its subcategories among infants of U.S.-born and foreign-born women, and (2) the extent to which maternal race/ethnicity modifies the relationship between maternal nativity and SUID rates.</p> Methods <p>Stratified and adjusted (for traditional demographic, clinical, and behavioral risk factors) Poisson regression analyses were performed on the National Center for Health Statistics linked 2021–2022 live birth-infant death database. Rates of SUID and its subcategories—sudden infant death syndrome (SIDS), accidental suffocation or strangulation in bed (ASSB), and unknown causes—were calculated for infants of women in the four largest U.S. racial/ethnic groups.</p> Results <p>Infants of U.S.-born women (<i>n</i> = 5,600,507) had an over three-fold greater SUID rate than infants of foreign-born women (<i>n</i> = 1,594,547): 115.5/100,000 vs. 34.8/100,000, RR = 3.3 (3.0, 3.6). Strikingly, the nativity disparity existed among infants of Non-Hispanic Asian (<i>n</i> = 431,532), Non-Hispanic Black (<i>n</i> = 1,025,573), Hispanic (<i>n</i> = 1,820,734) and Non-Hispanic White (<i>n</i> = 3,722,820) women: RR = 2.4 (1.7, 3.5), 4.9 (4.0, 6.1), 2.3 (2.0, 2.6), and 3.2 (2.5, 4.1), respectively. Maternal nativity disparities in SUID persisted after adjustment, overall (adjRR = 2.5 (2.3, 2.8)) and within each racial/ethnic group. Non-Hispanic Black infants had the widest disparity (adjRR = 3.3 (2.7, 4.1)). Similar results were observed for SIDS, ASSB, and unknown causes.</p> Conclusions for Practice <p>Infants of U.S.- vs. foreign-born women have higher rates of SUID and its subcategories independent of traditional risk factors. This nativity disparity is widest among Non-Hispanic Black women. These findings warrant further attention and research regarding differences in environment, infant sleep practices and SUID death investigation among foreign-born and U.S.-born women.</p>