In Australia, influenza hospitalises more children than any other vaccine preventable disease does. Children aged six months or older are recommended to receive annual influenza vaccines, and pregnant women are recommended vaccination to protect infants aged up to six months. However, vaccine uptake is low. This study explored influenza vaccination knowledge and behaviours of parents of children who were hospitalised for influenza, in order to inform strategies that target barriers to uptake.We conducted 27 semi-structured interviews with parents/caregivers during or shortly after their child's hospitalisation for laboratory-confirmed influenza in 2017. Questions were guided by the Social Ecological Model exploring all levels of influence on vaccination uptake from the intrapersonal through to policy, via the parents' perspective. Transcripts were inductively analysed. Themes were categorised into the components of the Capability-Opportunity-Motivation-Behaviour (COM-B) model.20/27 children were aged six months or older; 16/20 had not received an influenza vaccine in 2017. Mothers of 4/7 infants aged less than six months were not vaccinated in pregnancy. The themes regarding barriers to influenza vaccination were: (1) Limited Capability - misinterpretations and knowledge gaps, (2) Lack of Opportunity - inconvenient vaccination pathway, missing recommendations, absence of promotion to all, and the social norm, and (3) Missing Motivation - hierarchy of perceived seriousness, safety concerns, a preference for 'natural' ways. Though most parents, now aware of the severity of influenza, intended to vaccinate their child in future seasons, some harboured reservations about necessity and safety. When parents were asked how to help them vaccinate their children, SMS reminders and information campaigns delivered through social media, schools and childcare were suggested.Improving parents' and providers' knowledge and confidence in influenza vaccination safety, efficacy, and benefits should be prioritised. This, together with making influenza vaccination more convenient for parents, would likely raise vaccine coverage.