Patients with gestational diabetes mellitus and from racial/ethnic minority groups face disproportionate risk for type 2 diabetes. Lifestyle interventions, if accessible and acceptable to diverse patients, could advance diabetes prevention and mitigate racial/ethnic disparities. Here we describe overall and race/ethnicity-specific reach, acceptability, and perceived success from an effective telehealth diabetes prevention lifestyle program for patients with gestational diabetes mellitus, implemented in the Gestational Diabetes Effects on Moms (GEM) cluster-randomized controlled trial. GEM tested a program of 13 telephone sessions and behavior change techniques (BCTs, e.g., goal setting) in a healthcare system. We evaluated participation (completing ≥1 session), acceptability of BCTs, and perceived success reaching program goals. Among 1,087 patients (75.2% from minority groups), 50.3% participated. Participation rates were 61.7% among Black, 56.4% among Hispanic, 55.6% among multiracial/other, 53.0% among White, and 43.7% among Asian/Pacific Islander patients. Evaluation survey respondents (n = 433/547; 79.2%) largely rated BCTs as very helpful (range 40.9%-58.4%) or moderately helpful (27.3%-34.9%). Respondents from minority groups largely rated goal setting for weight management as very or moderately helpful, with fewer minority respondents rating it as only a little/not at all helpful than White respondents (p = .02). Black and White respondents reported more limited success reaching a healthy weight than Asian/Pacific Islander, Hispanic, and multiracial/other women (p = .005). A telehealth diabetes prevention lifestyle program demonstrated reach and acceptability across racial/ethnic groups. While perceived success can be improved among Black and White participants, such programs could promote access to preventive care and help mitigate disparities in diabetes risk.