The term 'SEN Support' describes the actions taken to support pupils and students in mainstream settings who have been identified as having special educational needs and disabilities (SEND), but who do not have an education, health and care (EHC) plan. Pupils receiving SEN support comprise just over 12% of all pupils in England. This report presents findings from a qualitative study conducted with mainstream primary and secondary school leaders and teachers to explore their approaches to identifying the needs of pupils receiving SEN support, how they meet these needs, and how they evaluate the effectiveness of the support provided. This study details findings from a qualitative study exploring mainstream primary and secondary school leaders' and teachers' approaches to: (1) identifying pupils that may have SEN support needs; (2) meeting the needs of pupils receiving SEN support; and (3) evaluating whether those needs have been met. The findings are based on 60 interviews conducted from March -- May 2021 with 15 primary teachers, 15 primary leaders, 15 secondary teachers and 15 secondary leaders, sampled from the Department for Education's (DfE's) Panel Study of Leaders and Teachers.