While previous research has identified numerous factors that contribute to item difficulty, studies involving large-scale reading tests have provided mixed results. This study examined five selected-response item types used to measure reading comprehension in the Pearson Test of English Academic: a) multiple-choice (choose one answer), b) multiple-choice (choose multiple answers), c) re-order paragraphs, d) reading (fill-in-the-blanks), and e) reading and writing (fill-in-the-blanks). Utilizing a multiple regression approach, the criterion measure consisted of item difficulty scores for 172 items. 18 passage, passage-question, and response-format variables served as predictors. Overall, four significant predictors were identified for the entire group (i.e., sentence length, falsifiable distractors, number of correct options, and abstractness of information requested) and five variables were found to be significant for high-performing readers (including the four listed above and passage coherence); only the number of falsifiable distractors was a significant predictor for low-performing readers. Implications for assessing reading comprehension are discussed.