This study determines prevalence of digit sucking and gingivitis, and association among age, sex, socioeconomic status, presence of digit-sucking habits, oral hygiene status (OHS), and gingivitis among a group of Nigerian children. Data of 992 children aged 1 to 12 years recruited through a household survey conducted in Osun State, Nigeria were analyzed. Information on age, sex, socioeconomic status, and history of digit-sucking habits were collected. Children were assessed for OHS and severity of gingivitis using the simplified oral hygiene index and the gingival index, respectively. Predictors of presence of gingivitis and poor oral hygiene were determined using multivariate logistic regression. One (0.2%) and 454 (93.0%) children aged 1 to 5 years had poor oral hygiene and mild gingivitis, respectively. Twenty-two (4.4%) and 361 (72.9%) children aged 6 to 12 years had poor oral hygiene and mild gingivitis, respectively. The odds of having poor oral hygiene (adjusted odds ratio [AOR]: 0.26; 95% confidence interval [CI]: 0.20 to 0.35; P <0.001) and gingivitis (AOR: 0.21; 95% CI: 0.14 to 0.31; P <0.001) was significantly reduced for children aged 1 to 5 years. The odds of having gingivitis was increased in children with low socioeconomic status (AOR: 2.09; 95% CI: 1.32 to 3.31; P = 0.002). There was no significant relationship among sex, digit sucking, OHS, and presence of gingivitis. A digit-sucking habit did not increase chances of having poor oral hygiene and gingivitis. Increasing age and low socioeconomic status were factors that significantly increased chances of having poor oral hygiene and gingivitis.