The purpose of the present study was to investigate and rank order by importance the contributions of various cognitive predictors to reading comprehension in third, seventh, and tenth graders. An exploratory factor analysis revealed that for third grade, the best fit was a four-factor solution including fluency, verbal reasoning, nonverbal reasoning, and working memory factors. For seventh and tenth grade, three-factor solutions with fluency, reasoning, and working memory factors were the best fit. The three and four-factor models were used in separate dominance analyses for each grade to rank order the factors by predictive importance to reading comprehension. Results indicated that fluency and verbal reasoning were the most important predictors of third grade reading comprehension. For seventh grade, fluency and reasoning were the most important predictors. By tenth grade, reasoning was the most important predictor of reading comprehension. Working memory was the least predictive of reading comprehension across all grade levels. These results suggest that inferential reasoning skills become an important contributor to reading comprehension at increasing grade levels.