Introduction: Malocclusion is a problem that affects the development of the dentition and, in most cases, has an environmental determinant. Objective: Determine the environmental factors associated with types of malocclusion in schoolchildren with early mixed dentition. Methods: The sample consisted of 275 schoolchildren who met the selection criteria, with an average age of 8.95 years, 151 boys and 124 girls. The clinical evaluation was carried out by a experienced specialist, the registration of environmental factors was carried out through a structured interview, body mass index and a questionnaire validated for socioeconomic status. For data analysis, SPSS version 25 software was used. Logistic regression analysis was used to evaluate the association of environmental factors with each type of malocclusion, establishing OR with 95% confidence intervals and a significance level of 5%. Results: The habit of mouth breathing showed that it is a factor associated with dental crowding (p = 0.049 < 0.05; OR = 1.723). Overweight protects against alteration of the tooth eruption (p = 0.039 < 0.05; OR = 0.459), compared to schoolchildren with normal nutritional status or malnutrition. Conclusions: It is concluded that there is an association between dental crowding and the habit of mouth breathing, between nutritional status and the alteration of the tooth eruption, being overweight a protective factor. In the other interactions evaluated, no association of another type of malocclusion with any environmental factor was found. © 2022, Editorial Ciencias Medicas. All rights reserved.