Social, Emotional and Mental Health (SEMH) needs, previously Behavioural, Emotional and Social Difficulties (BESD), is the most frequently occurring category of Special Educational Need (SEN) in secondary schools in England, associated with school exclusion and poorer outcomes in later life. This study explores the perceptions of young people of the "label" BESD/SEMH and their school experiences. A social constructionist grounded theory approach was used to analyse data from semi-structured interviews with nine young people with a statement of SEN for BESD. Findings show that eight of the participants were previously unaware of their classification of BESD and that it was predominantly negatively evaluated. The grounded theory model arising from the research describes the perceptions of young people of the struggles and strengths that they experience at school. Teacher-pupil relationships were found to contribute to both strengths and struggles at school depending on their perceived quality. Implications for policy and practice are discussed.