This study investigates the relation between maternal mental state expressions during story book reading and 3- to 5-year-old Turkish speaking children’s theory of mind (ToM) abilities. Thirty-two children completed ToM, executive functions, and standardized language tasks. Following these, parents read a wordless picture book to their children. Mothers’ mental state languages were coded in 3 levels of structural complexity: the word, the morphological, and the clause levels. At the word level we coded for the frequency and the diversity of mental state words (i.e., perception, physiological states, motivation/intention, desire, affect, cognitive, contrastive). At the morphological level we coded for modality for volitional wishes (-se, -sa) and modality for volitional suggestions (-e, -a). Mental state words with their subcategories were coded in accordance with their referents: (1) the child, the mother, or others (MSW-CMO) (2) story characters (MSW-SC). At the sentence level we coded for mental state causal explanations under two categories: (1) Explicit explanations and (2) Implicit Explanations. Results revealed that mothers’ total MSW was related to children’s ToM after controlling for strong predictors. Additionally, frequency of total MSW-CMO, cognitive-CMO, perception-CMO, perception-SC, and total perception word uses were correlated with children’s ToM. Furthermore, while cognitive words positively predicted children’ ToM, explanations for cognitive words negatively predicted children’s ToM. In line with correlational results that emphasize the role of perception words, an analysis that investigated the effects of perception, cognitive, and contrastive words found that the aggregate frequency of these categories predicted children’ ToM. Lastly, only mothers’ cognitive-CMO predicted children’s ToM.