We know that students' positive engagement with school is closely linked to their positive mental health. In particular, a positive engagement assists students to develop the human connections and resilience that reduces the risk of developing later mental health problems. What do students themselves say about what assists them to engage successfully with school? In particular, what is known of the views of students with high support needs in the area of mental health? The MindMatters Plus Project commissioned a review of existing studies of students' perspectives about engagement. This overview summarises the literature that typifies the three overlapping areas of school engagement, student voice and students with high support needs in the area of mental health, drawing on an extensive annotated bibliography of sources (available online at mmplus.agca.com.au/studeng_unheard_voices.php?x=13). The students about whom MindMatters Plus has a particular concern -- those who are at greater risk of having high support needs in the area of mental health--are often less likely to voice their opinion and concerns to adults. As a consequence, less is known about what they are saying about factors that engage them with school--theirs are frequently "unheard voices".