This meta-analysis aims to quantitatively synthesize the relation between the essential components of reading and reading comprehension in children whose first language is Spanish and who are learning to read in Spanish in a monolingual setting. Searches were conducted in WOS, Scopus, and ERIC from 2000 to 2021. We used a random effects model and Fisher’s z as an index of effect size. We found 33 studies involving 146 effect sizes between the essential components of reading and reading comprehension. The essential components included phonological awareness, morphological awareness, alphabetic principle, fluency, vocabulary, and oral comprehension. Results of the meta-analysis revealed that (1) most studies have focused on understanding the relation between phonological awareness or alphabetic principle and reading comprehension, (2) the largest effect sizes were between phonological awareness and reading comprehension, and between fluency and reading comprehension, and (3) there is a large heterogeneity across studies which is explained, in part, by factors such as age, country where the study was conducted, and the reading comprehension tests used. Implications for practice and future research are discussed.