The purpose of this study was to determine the relation between reading and working memory (WM) in the context of 3 major theories: the domain-specificity theory (debate) of WM, the intrinsic cognitive load theory, and the dual process theory. A meta-analysis of 197 studies with 2026 effect sizes found a significant moderate correlation between reading and WM, r = .29, 95% CI [.27, .31]. Moderation analyses indicated that after controlling for publication type, bilingual status, domains of WM, and grade level, the relation between WM and reading was not affected by types of reading. The effects of WM domains were associated with grade level: before 4th grade, different domains of WM were related to reading to a similar degree, whereas verbal WM showed the strongest relations with reading at or beyond 4th grade. Further, the effect of WM on reading comprehension was partialed out when decoding and vocabulary were controlled for. Taken together, the findings are generally compatible with aspects of the domain-specificity theory of WM and the dual process theory, but, importantly, add a developmental component that is not currently reflected in models of the relation between reading and WM. The findings suggest that the domain-general central executive of WM is implicated in early reading acquisition, and verbal WM is more strongly implicated in later reading performance as readers gain more experience with reading. The implications of these findings for reading instruction and WM training are also discussed.