This study had two aims. The first aim was to measure mental state understanding in institution-reared children by using a theory of mind (ToM) scale, and to examine the role of cultural context in sequencing of ToM acquisition. The other aim was to investigate ToM in relation to social competence and executive function (EF). Due to its pronounced role in mental state understanding and social interactions, we assessed receptive language as well. The participants were 107 institution-reared children aged 3 to 5 years in Turkey. Two visits were held within 2 days for behavioral assessments. In the first visit, the ToM scale was administered; in the second visit, the child was given the language test and the EF tasks. The social competence scales were completed by the child's primary care provider in the institution. Guttman scaling analysis revealed that an understanding of diverse beliefs developed earlier than knowledge access, favoring the "individualistic pattern." The regression analysis showed that EF was a significant predictor of ToM, but neither of them was associated with social competence when age was controlled. Receptive language predicted social competence and EF directly, and ToM indirectly through EF, pointing to the importance of this ability for early development.