SummaryThe risk of type 2 diabetes mellitus (T2DM) varies by ethnicity, but ethnic differences in response to diabetes prevention interventions remain unclear. This systematic review and meta‐analysis assessed ethnic differences in the effects of lifestyle interventions on T2DM incidence, glycemic outcomes (fasting glucose, 2‐h glucose, HbA_1c), anthropometric measures (weight, BMI, waist circumference), and lifestyle behaviors (physical activity, energy intake, energy from fat, fiber intake). MEDLINE, EMBASE, and other databases were searched (to June 15, 2020) for randomized and non‐randomized controlled trials on lifestyle interventions (diet and/or physical activity) in adults at risk of T2DM. Ethnicity was categorized into European, South Asian, East and Southeast Asian, Middle Eastern, Latin American, and African groups. Forty‐four studies were included in meta‐analyses. Overall, lifestyle interventions resulted in significant improvement in T2DM incidence, glycemic outcomes, anthropometric measures, physical activity, and energy intake (all P < 0.01). Significant subgroup differences by ethnicity were found for 2‐h glucose, weight, BMI, and waist circumference (all P < 0.05) but not for T2DM incidence, fasting glucose, HbA_1c, and physical activity (all P > 0.05). Few studies in non‐European groups reported dietary intake. Lifestyle interventions in different ethnic groups may have similar effects in reducing incidence of T2DM although this needs to be confirmed in further studies.