Background: We studied the hypothesis of socioeconomic equalization regarding adolescents' mental health problems by examining whether a low educational level of adolescents and their parents shows independent (cumulative) or dependent (including interactive) associations with adolescents' mental health problems, or whether equalization occurred. Methods: Cross-sectional data were obtained from the preventive Youth Health Care Centre in a relatively deprived Dutch former mining area. Participants were 1861 adolescents aged 13 or 14 years (response rate 71.7%). The self-administered Dutch version of the Strengths and Difficulties Questionnaire (SDQ) was used to identify adolescents' mental health problems. Multiple logistic regression analyses were used to examine the associations, and linear regression models to check the robustness of the findings. Results: A low educational level of adolescents was strongly related to their mental health problems (OR = 5.37; 95% CI: 3.31-8.70). The initially high odds ratios for adolescents with low-educated parents (OR = 1.72; 95% CI: 1.14-2.59) disappeared after controlling for the adolescents' own educational level (OR = 1.12; 95% CI: 0.73-1.74). In terms of interactions, no specifically increased odds were found, e.g. for low-educated adolescents with high-educated parents. Conclusion: There was no evidence for socioeconomic equalization regarding adolescents' mental health problems. Lower educated adolescents had substantially higher odds of having mental health problems, regardless of their parents' education. The odds may be affected by differences in intelligence and life events. Youth healthcare workers should collaborate closely with schools to intervene in time, particularly among low-educated adolescents. More interventions are probably needed to reduce these major inequities.