Background Meat-free diets may be associated with a higher risk of hip fracture, but prospective evidence is limited. We aimed to investigate the risk of hip fracture in occasional meat-eaters, pescatarians, and vegetarians compared to regular meat-eaters in the UK Biobank, and to explore the role of potential mediators of any observed risk differences. Methods Middle-aged UK adults were classified as regular meat-eaters (n = 258,765), occasional meat-eaters (n = 137,954), pescatarians (n = 9557), or vegetarians (n = 7638) based on dietary and lifestyle information at recruitment (2006–2010). Incident hip fractures were identified by record linkage to Hospital Episode Statistics up to September 2021. Multivariable Cox regression models were used to estimate associations between each diet group and hip fracture risk, with regular meat-eaters as the reference group, over a median follow-up time of 12.5 years. Results Among 413,914 women, 3503 hip fractures were observed. After adjustment