This systematic review synthesizes the evidence pertaining to the effects of public health programs to regularly treat all children with deworming drugs on child growth, hemoglobin, cognition, school attendance, school performance, physical fitness, and mortality. Evidence from 50 trials in low-to-high-burden settings suggests substantial evidence of no benefit of deworming in terms of hemoglobin, cognition, school performance, and mortality. For weight, contemporary studies do not show an effect, whereas unusually large effects were seen in studies conducted over 20 years ago.