The aim of the present study was to examine the influence of weight status on flexibility performance in Spanish youths (1475 boys and 1237 girls) aged 617 years, and to provide percentile values for two flexibility tests. Flexibility was assessed by the sit-and-reach and shoulder stretch tests. Participants were categorized as underweight, normal weight, overweight and obese. Girls had significantly better scores than boys in all the studied tests, except in the right-shoulder stretch test in the 67, 1415 and 1617-year-old groups, and in the left-shoulder stretch test in the 67, 89 and 1617-year-old groups. There was not a significant positive association between weight status and flexibility assessed by the sit-and-reach test. However, overweight and obese youths had significantly lower performance than their normal-weight counterparts in the shoulder stretch test. Underweight and normal-weight individuals had similar performances for both shoulder flexibility tests. In conclusion, percentiles values of the studied flexibility tests might be of interest to estimate the proportion of youths with high or low flexibility levels, as well as to evaluate the effects of alternative interventions.