Component skills and discourse frameworks of reading have identified characteristics of readers and texts that influence comprehension. However, these 2 frameworks have not previously been integrated in a comprehensive and systematic way to explain performance on any standardized assessment of reading comprehension that is in widespread use across a broad developmental spectrum. The current study undertook such an integration using the reading comprehension subtest of the Gates-McGinitie Reading Tests, investigating characteristics of the test’s reading passages and comprehension questions and the component reading skills of students in middle and high school (n = 1,190) in order to determine the extent to which each of these dimensions affect test performance, both on average and through interaction with one another. The component skills of reading included word reading, reading fluency, vocabulary, background knowledge, and working memory. Test questions were coded for their processing demands, specifically the need to recall information from test and to form text-based inferences, while text passages were measured on word frequency, sentence length, text cohesion, and genre. We found that better vocabulary and background knowledge were the most important reader characteristics in accounting for reading comprehension. The processing demands of test questions were not highly predictive of item difficulty. Rather, genre was the most important passage feature in explaining item difficulty. Reader-test interactions were present, but were not pronounced. We discuss the importance of these findings as they relate to the measurement of comprehension and the integration of component skills and text-discourse models of reading.