Childhood immunisations have contributed to saving millions of lives worldwide. However, a growing number of parents are declining immunisations, while other parents are choosing to delay them or opting for selective immunisations. These behaviours contribute to the reduction of herd immunity and to the possible resurgence of certain diseases. The aim of this extended literature review was to investigate factors that contribute to 'vaccine hesitancy' for childhood immunisation among parents. Seven qualitative studies were included in the review and examined using thematic analysis. The main themes identified were vaccine safety, effectiveness of vaccines and healthcare factors, which suggest that vaccine hesitancy is more complex than parents simply agreeing or disagreeing for their child to be immunised. A range of factors contribute to vaccine hesitancy and patients' decisions are highly influenced by their perceived need to research information about immunisation online. Healthcare professionals involved in childhood immunisations need to be aware of these factors and behaviours that attribute to vaccine hesitancy to enhance their professional practice.