BACKGROUND: Nutritionally inadequate diets in Ethiopia contribute to a persisting national burden of adult undernutrition, while the prevalence of noncommunicable diseases (NCDs) is rising. OBJECTIVES: To evaluate performance of a novel Global Diet Quality Score (GDQS) in capturing diet quality outcomes among Ethiopian adults. METHODS: We scored the GDQS and a suite of comparison metrics in secondary analyses of FFQ and 24-hour recall (24HR) data from a population-based cross-sectional survey of nonpregnant, nonlactating women of reproductive age and men (15-49 years) in Addis Ababa and 5 predominately rural regions. We evaluated Spearman correlations between metrics and energy-adjusted nutrient adequacy, and associations between metrics and anthropometric/biomarker outcomes in covariate-adjusted regression models. RESULTS: In the FFQ analysis, correlations between the GDQS and an energy-adjusted aggregate measure of dietary protein, fiber, calcium, iron, zinc, vitamin A, folate, and vitamin B12 adequacy were 0.32 in men and 0.26 in women. GDQS scores were inversely associated with folate deficiency in men and women (GDQS Quintile 5 compared with Quintile 1 OR in women, 0.50; 95% CI: 0.31-0.79); inversely associated with underweight (OR, 0.63; 95% CI: 0.44-0.90), low midupper arm circumference (OR, 0.61; 95% CI: 0.45-0.84), and anemia (OR, 0.59; 95% CI: 0.38-0.91) in women; and positively associated with hypertension in men (OR: 1.77, 95% CI: 1.12-2.80). For comparison, the Minimum Dietary Diversity-Women (MDD-W) was associated more positively (P < 0.05) with overall nutrient adequacy in men and women, but also associated with low ferritin in men, overweight/obesity in women, and hypertension in men and women. In the 24HR analysis (restricted to women), the MDD-W was associated more positively (P < 0.05) with nutrient adequacy than the GDQS, but also associated with low ferritin, while the GDQS was associated inversely with anemia. CONCLUSIONS: The GDQS performed capably in capturing nutrient adequacy-related outcomes in Ethiopian adults. Prospective studies are warranted to assess the GDQS' performance in capturing NCD outcomes in sub-Saharan Africa.