The present meta-analysis examined the overall average correlation (weighted for sample size and corrected for measurement error) between passage-level second language (L2) reading comprehension and 10 key reading component variables investigated in the research domain. Four high-evidence correlates (with 18 or more accumulated effect sizes: L2 decoding, L2 vocabulary knowledge, L2 grammar knowledge, first language [L1] reading comprehension), and six low-evidence correlates (L2 phonological awareness, L2 orthographic knowledge, L2 morphological knowledge, L2 listening comprehension, working memory, metacognition) were included in the study. For the four high-evidence correlates, a series of moderator analyses were also carried out to examine the effects of age, L2 proficiency, L1-L2 script and language distance, and measurement characteristics. The results showed that L2 grammar knowledge (r = 0.85), L2 vocabulary knowledge (r = 0.79), and L2 decoding (r = 0.56) were the three strongest correlates of L2 reading comprehension. The six low-evidence correlates had moderate-to-strong mean correlations, with L2 listening comprehension being the strongest correlate (r = 0.77) and metacognition (r = 0.32) being the weakest correlate. Age, some measurement characteristics, and L1-L2 language distance were found to be significant moderators for some reading components.