Tick NT, van der Ende J, Verhulst FC. Twenty-year trends in emotional and behavioral problems in Dutch children in a changing society. Objective: Research into changes in the prevalence of children’s psychiatric diagnoses has indicated an increase in recent decades. However, methodological problems may have influenced results. This study compared children’s emotional and behavioral problem levels across three population samples from different time points across 20 years, assessed with identical methodologies. Method: We compared Child Behavior Checklists and Teacher’s Report Forms across three population samples of 6- to 16-year olds, assessed in 1983, 1993, and 2003. Results: We found evidence for small increases in the mean population levels of parent-reported problems, and in the percentages of children with serious problems. These changes concerned mostly internalizing problems. Teacher reports showed less changes. Decreases in scores were found on several areas of competence. Changes were the strongest between 1993 and 2003. Conclusion: We found evidence for small increases in Dutch children’s problems. Further developments must be monitored, as this trend may continue and have serious societal consequences.