This study examined the role of reading amount as a mediator of the effects of intrinsic and extrinsic reading motivation on higher order reading comprehension (comprised of paragraph-and passage-level comprehension) in a sample of 159 fifth-grade elementary students. A positive association between intrinsic reading motivation and reading amount was assumed, whereas a negative contribution to reading amount was expected for extrinsic reading motivation. As control variables, lower order reading comprehension (comprised of word- and sentence-level comprehension), gender, and social desirability were taken into account. Structural equation analyses indicated that reading amount fully mediated the positive effect of intrinsic reading motivation on higher order comprehension, whereas extrinsic reading motivation exerted both indirect and direct negative effects on comprehension. Additional analyses confirmed a suppression effect and showed significant negative contributions of extrinsic reading motivation to reading amount and reading comprehension only when intrinsic reading motivation was simultaneously included as a predictor.