Background: Population-level evidence on suicide mortality among children and young people (CYP) with Special Educational Needs and Disabilities (SEND) is limited. SEND captures a broad and heterogeneous population, including children whose needs are recognised in educational settings regardless of recorded clinical diagnosis. Methods: We analysed 3,959,390 CYP aged 10-18 years in England using Growing Up in England (GUiE) data linked to death registrations. SEND provision was classified as no support, support or statement, using records from academic years 2001/02 to 2010/11. CYP were followed until age 25, death or 31 December 2022. Sex-stratified, age-adjusted Cox models estimated suicide by SEND provision. Results: In the cohort, 1,383,300 CYP (35%) had provision of support and 148,200 (4%) had a statement. During follow-up, 2,620 suicides occurred among 10- to 24-year-olds; 1,190 (45.4%) were among CYP with support and 130 (5%) among those with statements. Compared with males with no support, suicide was higher among males with provision of support (hazard ratio [HR]: 1.46; 95% CI: 1.33-1.61) and statements (HR: 1.32; 95% CI: 1.09-1.61). Among females, support provision was associated with higher risk of suicide (HR: 1.23; 95% CI: 1.05-1.44), while no significant difference was observed for those with statements (HR: 1.15; 95% CI: 0.69-1.92). Suicide rates were highest among CYP with social, emotional and mental health needs. Conclusions: CYP with SEND had elevated risk of suicide, particularly those receiving support without a statutory plan and those with social, emotional and mental health needs, highlighting the need for targeted prevention.