Objectives To assess public awareness of the risks and symptoms of cancer in children, teenagers, and young adults (CTYA) aged <18 years in Great Britain.Methods A face-to-face computer-assisted opinion survey was conducted by Ipsos MORI. Participants were a population-based sample of 1000 adults (475 men, 525 women) aged >18 years, with 26% having children aged 6-15 in their households. Questions covered perception about cumulative cancer risk, confidence in recognising signs and symptoms, recognition and perceived urgency of classical signs and symptoms.Results Only 32% of respondents felt confident in recognising CTYA cancer signs and symptoms. Symptoms deemed to require medical assessment within 48 hours by over 50% of participants included seizures/fits, blood in urine or stool, and persistent vomiting. All symptoms except one were selected for assessment within 3 months. On average, respondents identified 10.6 out of 42 classical signs and symptoms. The most recognised symptoms included lump, swelling in pelvis, testicle or breast (46%), blood in urine or stool (44%), changes to moles (43%), lump/swelling in the chest wall or armpits (41%) and weight loss (40%). The least recognised symptoms were early/late puberty (10%), developmental delay in children aged <2 years (11%) and slow growth (13%), with 8%, 2% and 6%, respectively, perceiving no need to discuss them with a doctor.Conclusions Public awareness of childhood cancer risks and symptoms is substantially lower compared with adult cancer awareness in Great Britain. These findings indicate knowledge and awareness gaps among the general public, highlighting the need for a child cancer awareness campaign.