Reading comprehension instruction was identified by the National Reading Panel as an effective instructional practice to improve students' reading comprehension. Teacher professional development (PD) is essential for effective reading comprehension instruction to occur in schools. The aim of this meta-analysis is to examine the extent to which teacher PD in reading comprehension impacted teacher knowledge or practice outcomes and student reading comprehension outcomes. Additionally, we explored whether various studies or PD characteristics were potential moderators of these outcomes. We identified 29 experimental and quasi-experimental studies, including 51 independent samples and 97 effect sizes. Using robust variance estimation, teacher PD in reading comprehension had a large effect (g = 0.947, p < 0.001) on teacher knowledge or practice and a small effect (g = 0.193, p < 0.001) on student reading comprehension. Results indicate teacher PD in reading comprehension is effective in improving teaching practices and student learning. However, more systematic research is needed to investigate effective PD components and other factors which may influence the impact of PD on teacher and student outcomes.