This cross-sectional study aimed to establish a relationship between the Normative Need for Orthodontic Treatment (NNOT) and oral health among Mexican adolescents aged 13–15 years old. A convenience sample of 424 subjects in Mexico City participated in the study. The dependent variable used was NNOT, which was determined via the dental health component (grades 4 and 5) of the Index of Orthodontic Treatment Need (IOTN). The variables for oral health were as follows: caries experience, oral hygiene, self-reported temporomandibular joint pain, and self-reported bruxism. Logistic regression models were fitted to determine the association between NNOT and oral health. The prevalence of NNOT was 66.0% (280/424), and the crowding was the most prevalent occlusal anomaly with 36.1% (n = 135). Multivariate models showed that subjects with NNOT were more than twice as likely to present poor hygiene (OR = 2.56; p = 0.001) as subjects presenting crowding (>4 mm) (OR = 1.99; p = 0.004) and increased overjet (>6 mm) (OR = 1.74; p = 0.046). Those schoolchildren who presented anterior guidance were 72% less likely to present NNOT (OR = 0.28; p < 0.001). In conclusion, the risk of presenting NNOT in Mexican adolescents is high, with a prevalence of over 50% of which the most prevalent occlusal anomaly was crowding. On the other hand, poor oral hygiene was associated with crowding and increased overjet.