Background: Migration of adult children may impact the health of aging parents who remain in low-and middle-income countries. Prior studies have uncovered mixed associations between adult child migration status and physical functioning of older parents; none to our knowledge has examined the impact on unmet caregiving needs. Methods: Data come from a population-based study of Mexican adults >50 years old. We analyzed 11806 respondents surveyed over an 11-year period. We used longitudinal targeted maximum likelihood estimation to estimate associations between having an adult child in the US and lower-body functional limitations, and both needs and unmet needs for assistance with basic or instrumental activities of daily living (ADLs/IADLs). Results: For women, having an adult child in the US at baseline and 2-year follow-up was associated with fewer lower body functional limitations (marginal risk difference (RD): −0.14, 95% CI: −0.26, −0.01) and fewer ADLs/IADLs (RD: −0.08, 95% CI: −0.16, −0.001) at 2-year follow-up. Having an adult child in the US at all three study waves was associated with more lower-body functional limitations at 11-year follow-up (RD: 0.04, 95% CI: 0.01, 0.06). Having an adult child in the US was associated with a higher prevalence of unmet needs for assistance at two (RD: 0.13, 95% CI: 0.04, 0.21) and 11-year follow-up for women (RD: 0.07, 95% CI: −0.02, 0.15) and 11-year follow-up for men (RD: 0.08, 95% CI: 0.00, 0.16).