Longitudinal studies have found associations between parenting and the development of conduct problems, and have found that resistant to control temperament moderates these associations. Intervention studies have found associations between intervention-induced changes in parenting and subsequent reductions in children's conduct problems. However, no study to date has evaluated whether parents' self-initiated efforts to change their parenting practices affect children's conduct problems and whether effects depend on children's temperament. The current study asked whether parents' concerted efforts, or campaigns, to increase their involvement and limit-setting were effective in reducing growth in conduct problems from late childhood to early adolescence. It also asked whether the effects of campaigns varied according to children's levels of temperamental resistance to control. Analyses statistically controlled for parenting practices and conduct problems before the campaigns, socioeconomic status, gender, and ethnicity. Results indicated that campaigns that included increased involvement and limit-setting were beneficial only for youths who were rated in early childhood as temperamentally resistant to control.