This study aims to relate readability degree with thematic structures, a concept based on Systemic Functional Linguistics (SFL). The texts chosen were fragments purposively sampled from three popular academic texts written by Pierre Bourdieu (1991) (Text 1), Norman Fairclough (1989) (Text 2), and Bill Ashcroft et al. (2002) (Text 3). The Theme properties examined include topical Theme selection, Theme (un)markedness, and Theme multiplicity. While the three texts shared thematic properties, they also showed dissimilarities. The topical Themes in the three texts were mostly realized by subjects (unmarked Themes), followed by adjuncts (marked Themes). Interestingly, the results further show that Text 2 thematized verbs (marked Themes), while Text 1 and Text 3 did not. Although multiple Themes are found in Text 1 and Text 3, they are not used as frequently as they are in Text 2. Overall, the thematic properties of Text 2 make it more interactive and cohesive than Text 1 and Text 3 and, therefore, more readable. Five respondents were conveniently sampled to grade the readability of the selected texts. They found Text 2 the most readable of all, suggesting the linkage between the thematic properties and readability of the texts. This study is pedagogically informative in that teachers are advised to consider the thematic properties of the texts they use in their classroom as these affect the readability of the texts.