Background: Mental health problems (MHPs) in preschoolers are precursors of mental disorders which have shown to be associated with suffering, functional impairment, exposure to stigma and discrimination, as well as enhanced risk of premature death. A better understanding of factors associated with MHPs in preschoolers can facilitate early identification of children at risk and inform prevention programs. This cross-sectional study investigated the association of risk and protective factors with MHPs within a German representative community sample. Methods: MHPs were assessed in a sample of 391 preschoolers aged 3-6 years using the Strength and Difficulties Questionnaire (SDQ). The effects of parental MHPs, children’s temperament, parental socioeconomic status (SES), social support and perceived self-competence on MHPs were assessed using bivariate and multivariate logistic regression analyses that controlled for sociodemographic characteristics. Results: Overall, 18.2% of preschoolers were classified as ‘borderline or abnormal’ on the total difficulties score of the SDQ. Bivariate analyses showed that parental MHPs, children’s difficult temperament, and parental low SES increased the likelihood, whereas high perceived parental competence decreased the likelihood of preschool MHPs. In the multivariate analyses, only difficult child temperament remained significantly associated with preschool MHPs when other variables were controlled. Conclusions: The results underline the importance of children’s difficult temperamental characteristics as a risk factor for mental health in preschoolers and suggest that these may also be an appropriate target for prevention of preschool MHPs. More research on specific aspects of preschool children’s temperament, the socioeconomic environment and longitudinal studies on the effects of these in the development of preschool MHPs is needed.