["Family Relations, EarlyView. ", "\nABSTRACT\n\nBackground\nExtensive research highlights the adverse effects of economic adversity on children's self‐regulation development. However, less is known about the impact of material hardship, which directly reflects unmet material needs within families.\n\n\nObjective\nThe current study examines transient fluctuation and persistent exposure to material hardship in relation to children's behavioral self‐regulation trajectories during the transition from early to middle childhood (ages 3 to 9).\n\n\nMethods\nUsing data from the Future of Families and Child Wellbeing Study (N = 4391), we applied multilevel linear mixed models to capture the effects of within‐person transient fluctuations and between‐person persistent exposure to material hardship on behavioral self‐regulation trajectories.\n\n\nResults\nResults indicated that transient increases in material hardship were associated with contemporaneous declines in behavioral self‐regulation. Higher average levels of persistent exposure to material hardship were linked to lower initial behavioral self‐regulation at age three but did not predict the rate of change in behavioral self‐regulation over time. Maternal marital status moderated this relationship, with children of married mothers showing a buffering effect against the negative association between persistent material hardship and initial behavioral self‐regulation at age three.\n\n\nImplications\nThese findings emphasize the importance of addressing both acute and chronic material hardship through tailored early prevention and intervention programs to promote behavioral self‐regulation among economically disadvantaged children.\n\n"]