The purpose of this research was to examine the new concept of, ‘psychosocial and academic trust alienation theory’; the potential influence of self-concept, self-esteem and trust as barriers to student engagement. The study was conducted in a Higher Education University campus located within a 16-19 year old Further Education Institution.A constructivist epistemology, underpinned by symbolic interaction theory utilising a mixed methods approach formed the research design. The sample population were students enrolled at the participating institution and employed teaching staff. Quantitative surveys were completed by 39 students, supported by two qualitative staff focus groups and one qualitative student case study to examine an outlier result. Findings suggest 87% of the student participant sample aligned with the ‘psychosocial and academic trust alienation theory’. Barriers to student engagement were; specific classroom and assessment activities, relationships with teaching staff and peers, staff absences and staff turnover, all having a significant impact on students’ psychosocial and academic trust. The contribution of this research to the field of Higher Education is three-fold; firstly, findings support the ‘psychosocial and academic trust alienation theory’, secondly it provides insights into the psychological barriers to engagement for the Widening Participation student demographic, thirdly it proposes practical strategies for supporting Widening Participation students in Higher Education. Recommendations for practice include i) counselling, coaching and mentoring support from teaching staff, ii) initiatives to reduce staff turnover and sickness, iii) social pedagogical teaching approaches, iv) teacher training, and, v) peer based learning opportunities to cultivate communities of practice. These strategies could strengthen Widening Participation student’s psychosocial and academic trust, thus reducing barriers to student engagement in Higher Education, contributing to increased social mobility success rates in the United Kingdom and beyond.