Objective: Depression is a public health crisis, and scalable, affordable interventions are needed. Although many psychosocial interventions are effective, there is little research investigating their sustained, long-term influence on well-being. The purpose of this study was to examine whether a prenatal mindfulness intervention with demonstrated benefit for women's depressive symptoms during the early postpartum period would exert effects through 8 years. Method: The sample of 162 lower income women was racially and ethnically diverse. Women were assigned to receive an 8-week mindfulness-based intervention during pregnancy (MIND) or treatment as usual (TAU). Repeated assessments of depressive symptoms were collected using the Patient Health Questionnaire-9 at baseline, postintervention, and following childbirth (1, 2, 3-4, 5, 6, and 8 years from baseline). The most recent assessment of depressive symptoms was collected during the COVID-19 pandemic. Results: MIND and TAU women were equivalent on sociodemographic factors and depressive symptoms at baseline. Depressive symptoms at all follow-up assessments through 8 years were significantly lower among women in MIND compared to TAU. The odds of moderate or higher depressive symptoms were greater among TAU compared to MIND women at all time points except the 6-year assessment. By Year 8, 12% of women in MIND reported moderate or more severe depressive symptoms compared to 25% of women in TAU. Conclusions: Results suggest the effects of a group-based psychosocial intervention during pregnancy may endure for years, well beyond the initial perinatal period. Investing in prevention and intervention efforts for mental health during pregnancy may have sustained benefits for the well-being of women. This document is copyrighted by the American Psychological Association or one of its allied publishers.This article is intended solely for the personal use of the individual user and is not to be disseminated broadly.Elissa S. Epel received funding from Grant U01 HL097973 from the National Heart, Lung, and Blood Institute. Nicole R. Bush received funding from Grants R01 HL116511-02 from the National Heart, Lung, and Blood Institute and UL1 TR000004 from the National Institute of Health and also from the Robert Wood Johnson Foundation, Lisa Stone Pritzker Family Fund, and Lisa and John Pritzker Family Foundation. Danielle S. Roubinov received funding from Grant K23MH1137019 from the National Institute of Mental Health.Danielle S. Roubinov played the lead role in writing of the original draft, supporting role in formal analysis and equal role in conceptualization and methodology. Elissa S. Epel played lead role in funding acquisition and supporting role in supervision and writing of review and editing. Michael Coccia played lead role in data curation and formal analysis. Kimberly Coleman-Phox played a supporting role in reviewing and editing and equal role in project administration. Cassandra Vieten played a supporting role in supervision and reviewing and editing and equal role...