Colombia is experiencing a nutrition transition, characterised by nutritionally poor diets and an increased prevalence of non-communicable diseases (NCD). We aimed to investigate the association between diet quality and general health outcomes related to the risk of NCD, in a nationally representative sample of Colombian adolescents and adults.Cross-sectional analysis. The Alternative Healthy-Eating Index (AHEI) was derived to calculate diet quality. Adjusted regressions were used to examine the association between AHEI, self-perceived general health status (GHS) and anthropometric variables (i.e. age-specific z-scores for height, and BMI for adolescents; waist circumference and BMI for adults).Nationally representative data from the Colombian National Nutrition Survey (ENSIN) 2010.Adolescents aged 10-17 years (n 6566) and adults aged ≥18 years (n 6750).AHEI scores were similar between adolescents (mean 29·3 ± 7·2) and adults (mean 30·5 ± 7·2). In the whole sample, a better diet quality (higher AHEI score) was associated with worse self-perceived GHS (adjusted (a) β-coefficient: -0·004; P < 0·001) and with a smaller waist circumference ((a) β-coefficient: -0·06; P < 0·01). In adults, a higher AHEI score was negatively associated with BMI ((a) β-coefficient: -0·02; P < 0·05), whilst in adolescents it was associated with a reduced height-for-age z-score ((a) β-coefficient: -0·009; P < 0·001).A better diet quality was associated with reduced prevalence of predictors of NCD and with some indicators of general health in the Colombian population. In light of the high prevalence of overweight, our findings support the need for public health interventions focused on sustainable positive changes in dietary habits in the general population.