BackgroundWhile text reading is still a preferred form of learning, topic interest can be considered an important predictor of reading comprehension. However, the nature of the relationship between interest and comprehension is not yet fully understood. AimsThe present study investigates whether topic interest is related to comprehension when measured in advance and whether two indicators of attention (i.e., mind wandering and cognitive coupling) mediate this relation. SampleParticipants were 238 university students. MethodsParticipants rated their interest in three different topics. One week later, they read one text on each of these topics. The texts’ levels of difficulty were manipulated to change during reading. Measured variables during reading were the individual adaptation of the reading speed to the text difficulty (cognitive coupling) and the frequency of mind wandering. In addition, comprehension was measured after reading each text. ResultsPreliminary assessed topic interest was found to be indirectly but not directly associated with reading comprehension. Specifically, topic interest negatively predicted mind wandering during reading, while mind wandering was, in turn, negatively associated with reading comprehension. In addition, partial evidence was found for the mediating role of cognitive coupling. ConclusionsThe present study adds to the research by showing that topic interest can predict future mind wandering and one type of cognitive coupling. Because mind wandering was, in turn, negatively related to reading comprehension, the study's findings further suggest that topic interest should be encouraged to minimize harmful mind wandering, promote adaption to text properties, and thus improve comprehension.