To explore the association between acculturation among foreign-born (FB) women, gestational diabetes (GDM) and GDM-associated adverse birth outcomes, we conducted a retrospective cohort study of 34,696 singleton pregnancies from Houston, TX, between 2011 and 2022. FB women (n = 18,472) were categorized based on years of residence in US (0–5, 6–10, and > 10 years), while US-born women (n = 16,224) were the reference group. A modified Poisson regression model determined the association between acculturative level and GDM within the entire cohort and stratified by race/ethnicity. Compared to US-born women, FB women with 0–5 years [adjusted relative risk (RRadj.) 1.27, 95% confidence interval [CI] 1.14–1.42)], 6–10 years (RRadj. 1.89, 95%CI 1.68–2.11) and > 10 years in the US (RRadj. 1.85, 95%CI 1.69–2.03) had higher risk of GDM. Results were consistent for all racial/ethnic groups, although associations were not significant at 0–5 years. FB women had lower risk of other adverse pregnancy outcomes, except for preeclampsia with severe features at higher levels of acculturation. Results were similar among those with and without GDM. In conclusion, FB status increases risk of GDM among all racial/ethnic groups but is elevated with higher acculturation levels.