This research aimed to develop a theoretically coherent account of the significance of student voice in understanding the secondary experiences of students with 'SEN/D'. The research question was: 'In what ways can student voice increase our current knowledge and understanding of inclusive processes?' The study utilised a multiple-case study design (Yin, 2009). Two secondary schools in each of two different national contexts (England and Greece) were recruited, from which 12 secondary students with SEN/D were selected as participants (3 from each school). The study's methods included classroom observations, interviews combined with participatory methods for eliciting student voice and the systematic use of a research diary. The fieldwork in each school included student observations during a school day; 'guided tours' combined with photo generation; and two separate individual interviews with each student combined with photo elicitation and other child-friendly activities. Collected in a range of contexts and situations, the student accounts were also complemented by data obtained though qualitative interviews with the school staff (SENCOs, SEN teachers and TAs). The study followed a dialectical approach to analyse and interpret the data, by combining the 'objective' bio-ecological theory of child development (Bronfenbrenner, 2005) with the 'subjective' student voice approach. The data analysis process included a two-stage analysis of the interview data. In the first stage, twelve 'personal experience' stories were developed to illuminate each participant's voice, using an inductive approach. In the second stage, data were examined for common themes and ideas following the structures of the bio-ecological (Process-Person-Context-Time) framework, which were further scrutinised through the study's student voice critical framework. The analysis showed that students' individual characteristics (such as their status in relation to 'SEN/D', their particular abilities/skills, level of motivation, temperament) considerably affected their experiences in both contexts. Students reported few instances of peer acceptance and having fewer friends and social interactions compared to their classmates. A general lack of interaction with mainstream teachers was reported in and out of the classroom. Divergent and often conflicting discourses emerged regarding the interactions of the students with the special support staff. While certain aspects of secondary school life (such as the inclusive school ethos and the flexibility of support) were perceived positively by students, other aspects (such as frequent exams and grades) were found to affect student experiences negatively regardless of the particular school or national context. By and large, the findings of this study indicated that the way students perceive their individual characteristics, their relationships with key people in school and their multi-level ecological system environments are inextricably intertwined in shaping their school experiences. The unique contribution of this study lies in the demonstration of the value of student voice to the actual meaning of the process of inclusion. Focusing on student voice contributed to a more holistic analysis of the development of young people in their school environments by: highlighting issues of power and identity; illuminating many of the key factors in the PPCT model and explaining their perceived significance; providing evidence for the interactions between PPCT elements; and finally, by identifying contradictions between students' and staff's perceptions. Overall, this study suggests that this dialectical view of student voice and the bio-ecological framework provides opportunities for a deeper understanding of the experiences of students with SEN/D in diverse settings and educational systems. In this way, the study enriches student voice and inclusive research in the secondary education level.