Since the turn of the millennium, there has been a surge of interest in diverse forms of spontaneous thinking, such as mind-wandering, and their associated brain networks. Studies demonstrate the pervasiveness of these phenomena as well as their effects on education-relevant domains such as academic skills, well-being, creativity, executive functions, and socioemotional competencies. Based on a neurophenomenological approach and drawing on cognitive and neuroscience research, this article reviews this field and develops a framework for understanding deliberate and nondeliberate states of students' minds in the classroom and their associated brain circuitry. Different approaches to these states are examined from an educational perspective and ways in which this discourse can further be developed are suggested.