Although substantial research indicates motivation contributes significant variance to reading comprehension in upper elementary students, research with students in primary grades has focused, instead, on the relation of motivation to word reading. Assessment of reading motivation in 68 first and second graders indicated word and nonword reading were related to perceived competence in reading, whereas reading comprehension was significantly related to subjective value for reading. Motivation contributed significant, unique variance to reading comprehension concurrently and longitudinally (n = 31), beyond decoding ability, verbal ability, and reading-specific executive function. Findings have implications for theories of reading comprehension.