BackgroundChronic hepatitis B (HBV) infection can lead to life-threatening liver disease. In the UK, approximately 180,000 people are carriers. The disease is underdiagnosed and undertreated.AimAs part of a nurse-led intervention aimed at improving HBV contact-tracing and management, we ascertained GPs’ understanding of HBV and their perceived barriers and enablers to HBV diagnosis.MethodIn 2015, we asked 1324 GPs across 2 England regions about HBV-related knowledge and practice, using a questionnaire. We reported the proportion of GPs answering each question, with 95% confidence intervals (95% CI).Results254 GPs (18%) replied. Of those, 189(74%, 95%CI 68–79%) correctly identified hepatitis B surface antigen as a marker of current HBV infection, and 154 (61%, 95% CI = 54 to 66%) recognised IgM anti-HBc as a marker for differentiating acute from chronic cases. 219 GPs (86%, 95% CI = 81 to 90%) believed HBV knowledge among patients to be one of the main enablers to improved testing uptake and 208 (82%, 95% CI = 77 to 86%) identified lack of HBV knowledge among patients as a barrier to testing. Of all GP responders, 227 (89%, 95% CI = 85 to 93%) reported HBV training and education would be beneficial, and 185 (73%, 95% CI = 67 to 78%) reported knowledge of treatment options as a knowledge gap.ConclusionGPs perceive gaps in knowledge among patients and healthcare professionals as a factor potentially contributing to the under-ascertainment of chronic hepatitis B in England. Improving HBV awareness and knowledge among patients, their contacts, and increasing HBV-focused training for GPs, particularly in the interpretation of laboratory results and the treatment options, can improve case ascertainment and chronic HBV management in primary care.