The current project has two aims: 1) It aims at examining relations between reading motivation (RM) and mind wandering (MW). Prior research on MW has shown that individuals who experience MW frequently while reading show worse comprehension (e.g., McVay & Kane, 2012; Smallwood, McSpadden, & Schooler, 2008). RM, on the other hand, has been identified as a relatively robust positive predictor of comprehension in both cross-sectional (e.g., Wang & Guthrie, 2004) and longitudinal studies (e.g., Becker, McElvany, & Kortenbruck, 2010). One explanation suggested by this research is that highly motivated readers are more likely to engage in reading behavior that is beneficial for the construction of a rich mental model of a given text, whereas lowly motivated readers are more likely to process the text superficially (Schiefele et al., 2012). Based on these findings, we argue that highly and lowly motivated readers differ in the contents of their thoughts during reading. Specifically, we here hypothesize that highly motivated readers are more likely to elaborate a text’s contents and to monitor their reading behavior and, as a result, are less likely to experience MW during reading. Given that MW is usually negatively related to comprehension, reduced MW in highly motivated readers may thus be a major reason for why RM is usually positively correlated with reading comprehension. In other words, MW may be an important mediator process that partially explains the relation between RM and comprehension. 2) A second aim of the present project is to examine the relations between trait-level MW and state-level MW with regard to their effects on reading comprehension. In a previous paper, we found that trait-level MW (daydreaming) had both positive and negative effects on comprehension (Soemer et al., 2019). The negative part was mediated by state-level MW; that is, individuals with a high propensity to mind-wander in various situations tend to do so also during reading. The positive part, however, remained unexplained. We here hypothesize that trait-level MW might be decomposed into a ‘positive-constructive’ and a ‘poor-attention’ component, along the lines of Huba et al. (1981), and that these components differentially affect reading comprehension. Accordingly, the ‘poor-attention’ component is strongly related to state-level MW during reading, whereas the ‘positive-constructive’ component is not. In contrast, the ‘positive-constructive’ component is strongly related to elaborative processes during reading, which support comprehension, whereas the ‘poor-attention’ component is not. Becker, M., McElvany, N., & Kortenbruck, M. (2010). Intrinsic and extrinsic reading motivation as predictors of reading literacy: A longitudinal study. Journal of Educational Psychology, 102, 773–785. Huba G. J., Aneshensel C. S., Singer J. L. (1981). Development of scales for three second-order factors of inner experience. Multivariate Behavioral Research, 16, 181–206. McVay, J. C., & Kane, M. J. (2012). Why does working memory capacity predict variation in reading comprehension? On the influence of mind wandering and executive attention. Journal of Experimental Psychology: General, 141, 302–320. Schiefele, U., Schaffner, E., Möller, J., & Wigfield, A. (2012). Dimensions of reading motivation and their relation to reading behavior and competence. Reading Research Quarterly, 47, 427–463. Smallwood, J., McSpadden, M., & Schooler, J. W. (2008). When attention matters: The curious incident of the wandering mind. Memory and Cognition, 36, 1144–1150. Soemer, A., Idsardi, H. M., Minnaert, A. & Schiefele, A. (2019). Mind wandering and reading comprehension in secondary school children. Learning and Individual Differences, 75, 101778. Wang, J.H.-Y., & Guthrie, J.T. (2004). Modeling the effects of intrinsic motivation, extrinsic motivation, amount of reading, and past reading achievement on text comprehension between U.S. and Chinese students. Reading Research Quarterly, 39, 162–186.