<p>Despite extensive research on reading motivation and reading comprehension, the mechanisms linking these constructs remain insufficiently understood. Moving beyond direct association models, the present study adopts a process-based perspective grounded in the Direct and Indirect Effects of Reading (DIER) framework to examine how reading motivation operates within a hierarchical system of reading processes. Specifically, we test a sequential mediation model linking reading motivation to reading comprehension through decoding, text-level performance, and reading fluency in a highly transparent orthography. Data were collected from 201 fifth-grade Turkish students and analyzed using regression-based sequential mediation with bootstrapping. Findings revealed that reading motivation exerted both direct and indirect effects on comprehension; however, these effects were not uniformly distributed across pathways. Notably, decoding did not contribute directly to comprehension, whereas reading fluency emerged as the dominant mediating mechanism. This pattern indicates that motivation influences comprehension primarily through efficiency-based processes that regulate the coordination of reading performance. These findings advance process-oriented models of reading by suggesting that reading comprehension may be understood as a coordinated system in which processing efficiency plays an important role in supporting comprehension outcomes. Critically, the study provides empirical evidence that the weighting of these pathways is shaped by orthographic characteristics, with fluency assuming a central role in transparent and morphologically complex languages.</p>