Theory of Mind (ToM) is defined as the ability to infer other s internal mental states. There is a consensus in the literature that ToM is a sociocognitive marker of Autism Spectrum Disorder-ASD. Performance is assessed in majority from false belief paradigm. However, there is a need for more accurate assessment tools, which include: complexity of the construct, interface with other cognitive domains as executive functions. The purpose of this work was to develop and verify validity’s evidences of a new instrument who evaluates differents ToM domains for diagnostic support in children with ASD. This study was registered in the Research Ethics Committee of Pontifical Catholical University of Rio de Janeiro-PUC-Rio. The project was divided into five studies, ranging from a literature review of ToM tasks used in assessments of ASD children, to show validity evidences of the instrument nominated Battery of Theory of Mind-BToM. The results showed BToM has evidence of content and construct validity as well as accuracy. In addition, it identifies Mental States and Verbalizations tasks as possible sociocognitive markers on diagnoses of lighter ASD phenotypes.