Abstract Background The association between overweight and gastrointestinal symptoms has been recently studied in the literature; however, few studies have evaluated the association between overweight and constipation in adolescents in a community-based sample. The aim of this study was to analyze the prevalence of constipation and its association with being overweight in a community-based survey with adolescents. Methods This cross-sectional study included 1,077 adolescents who were enrolled in five schools in the city of Sao José dos Campos, Brazil. Constipation was defined according to modified and combined Rome III criteria for adolescents and adults. Being overweight was defined as a body mass index (BMI) that was equal to or greater than that of the 85th percentile for age and gender. Results Constipation was diagnosed in 18.2% (196/1077) of the included adolescents. There was no significant difference in the prevalence of constipation in males and females who were both younger and older than 14 years. Fecal incontinence was observed in 25 adolescents, 22 (88.0%) of whom were diagnosed as being constipated. The prevalence of being overweight was found in 13.5% (145/1077) of the study population. The prevalence of constipation was observed to be similar in adolescents who were (19.4%; 28/144) and were not (18.0%; 168/933) overweight (p = 0.764; OR = 1.10). Fecal incontinence that was associated with constipation was more frequent in adolescents who were overweight (37.0%; 8/28) than in adolescents who were not overweight (8.5%; 14/168; p = 0.005; OR = 4.40). Conclusions The prevalence of constipation was high among the investigated adolescents. There was no association between being overweight and constipation; however, an association between being overweight and fecal incontinence in constipated adolescents was confirmed.