Skilled reading comprehension is an important goal of educational instruction and models of reading development. In this study, the authors investigated how core skills surrounding morphemes, that is, the minimal units of meaning in language, support the development of reading comprehension. The authors specifically contrast the roles of morphological awareness and morphological analysis; the first refers to the awareness of and ability to manipulate morphemes in language, and the second refers to the use of morphemes in inferring the meaning of unfamiliar morphologically complex (multimorphemic) words. The authors evaluated these morphological skills in 197 English-speaking students who were followed from grade 3 to grade 4; the analyses used stringent autoregressor controls to home in on predictors of gains over time. In addition to morphological awareness and morphological analysis, the authors assessed students' reading comprehension and controls for word reading, vocabulary, phonological awareness, nonverbal ability, and age. Multivariate autoregressive path analysis revealed that morphological analysis, but not morphological awareness, predicted gains in reading comprehension. Morphological awareness, for its part, predicted gains in morphological analysis. Taken together, the findings allude to a developmental trajectory whereby students' use of morphemes to infer the meanings of unfamiliar complex words supports the development of reading comprehension over time. The development of this skill, in turn, appears to be supported by a more general awareness of morphemes in language. These findings contribute to theory and reading instruction by clarifying the ways in which morphological skills support the development of students' reading comprehension.