The current study employed a meta-analytic approach to investigate the relative importance of component reading skills to reading comprehension in struggling adult readers. A total of 10 component skills were consistently identified across 16 independent studies and 2,707 participants. Random effects models generated 76 predictor–reading comprehension effect sizes among the 10 constructs. The results indicated that six of the component skills exhibited strong relationships with reading comprehension (average rs ≥ .50): morphological awareness, language comprehension, fluency, oral vocabulary knowledge, real word decoding, and working memory. Three of the component skills yielded moderate relationships with reading comprehension (average rs ≥ .30 and < .50): pseudoword decoding, orthographic knowledge, and phonological awareness. Rapid automatized naming (RAN) was the only component skill that was weakly related to reading comprehension (r = .15). Morphological awareness was a significantly stronger correlate of reading comprehension than phonological awareness and RAN. This study provides the first attempt at a systematic synthesis of the recent research investigating the reading skills of adults with low literacy skills, a historically understudied population. Directions for future research, the relation of our results to the children’s literature, and the implications for researchers and adult basic education programs are discussed.