Neurological studies reveal that theory of mind is a part of social intelligence in human beings and a requirement for language acquisition. Appropriate use of language is one important aspect of social life. Theory of mind is defined as understanding mental representations, and effective language use relies on monitoring the probable mental states of the listener, and making inferences about the mental states of the speaker. As the ability to understand our own minds and those of others is central to what it means to be a human, considering theory of mind and language as separate abilities in human mind may make little sense. The aim of this article is to illustrate the possible cause-effect relationship between language and theory of mind and the mutual role they play in human social life, by adopting the Relevance Theoretic Pragmatics framework based on a definition of relevance and two general cognitive and communicative principles. As a remarkable part of assessing the theory of mind and its intimate relation with language lie in developmental psychology, a great deal is taken from research on child psychology.