The purposes of this review were to determine: (1) if different writing activities were more effective than others in improving students' reading comprehension, and (2) if obtained differences among writing activities was related to how reading comprehension was measured? Meta-analysis was used to examine these questions across studies involving students in grades 1-12. Nineteen studies were located that met inclusion criteria, resulting in 4 writing activities comparisons with 4 or more studies per comparison: summary writing versus answering questions (k = 5), summary writing versus note taking (k = 7), answering questions versus note taking (k = 4), and answering questions versus extended writing activities (k = 6). Effect sizes calculated for each writing activities comparison indicated there were no statistically significant differences for any of these comparisons when effects were averaged over all reading comprehension measures, excluding treatment-inherent measures. However, statistically significant differences were found for two of the comparisons on specific measures. Extended writing enhanced reading comprehension better than question answering on measures where comprehension was assessed via an extended writing activity, whereas summary writing enhanced reading comprehension better than question answering on a free recall measure. The results provide limited support for the theoretical viewpoint that writing activities are differentially effective in improving reading comprehension based on how closely the writing activities are aligned with a particular measure.