The purpose of the present study was to examine the effects of a program that offered sustained strategic reading instruction on reading abilities of third and fourth graders. The study was conducted among 1,469 children from 40 schools in the Netherlands. Schools were randomly assigned to either the experimental or control group. Multilevel analyses showed positive effects on knowledge of reading strategies after one year of intervention at the end of Grade 3. At the end of Grade 4, there were also positive intervention effects on reading comprehension. No significant interaction effects were determined for age, gender, SES, or ethnic/linguistic background. The intervention effects were also not dependent on the level of the student's nonverbal intelligence, vocabulary, or decoding skills.