BACKGROUND: Childhood vaccination is an effective way to prevent serious childhood illnesses, but many children do not receive all the recommended vaccines. There are various reasons for this; some parents lack access because of poor quality health services, long distances or lack of money. Other parents may not trust vaccines or the healthcare workers who provide them, or they may not see the need for vaccination due to a lack of information or misinformation about how vaccinations work and the diseases they can prevent.Communication with parents about childhood vaccinations is one way of addressing these issues. Communication can take place at healthcare facilities, at home or in the community. Communication can be two-way, for example face-to-face discussions between parents and healthcare providers, or one-way, for instance via text messages, posters or radio programmes. Some types of communication enable parents to actively discuss vaccines and their benefits and harms, as well as diseases they can prevent. Other communication types simply give information about vaccination issues or when and where vaccines are available. People involved in vaccine programmes need to understand how parents experience different types of communication about vaccination and how this influences their decision to vaccinate. OBJECTIVES: The specific objectives of the review were to identify, appraise and synthesise qualitative studies exploring: parents' and informal caregivers' views and experiences regarding communication about childhood vaccinations and the manner in which it is communicated; and the influence that vaccination communication has on parents' and informal caregivers' decisions regarding childhood vaccination. SEARCH METHODS: We searched MEDLINE (OvidSP), MEDLINE In-process and Other Non-Index Citations (Ovid SP), Embase (Ovid), CINAHL (EbscoHOST), and Anthropology Plus (EbscoHost) databases for eligible studies from inception to 30 August 2016. We developed search strategies for each database, using guidelines developed by the Cochrane Qualitative Research Methods Group for searching for qualitative evidence as well as modified versions of the search developed for three related reviews of effectiveness. There were no date or geographic restrictions for the search. SELECTION CRITERIA: We included studies that utilised qualitative methods for data collection and analysis; focused on the views and experiences of parents and informal caregivers regarding information about vaccination for children aged up to six years; and were from any setting globally where information about childhood vaccinations was communicated or distributed. DATA COLLECTION AND ANALYSIS: We used maximum variation purposive sampling for data synthesis, using a three-step sampling frame. We conducted a thematic analysis using a constant comparison strategy for data extraction and synthesis. We assessed our confidence in the findings using the GRADE-CERQual approach. High confidence suggests that it is highly likely that the review finding is a reasonable representation of the phenomenon of interest, while very low confidence indicates that it is not clear whether the review finding is a reasonable representation of it. Using a matrix model, we then integrated our findings with those from other Cochrane reviews that assessed the effects of different communication strategies on parents' knowledge, attitudes and behaviour about childhood vaccination. MAIN RESULTS: We included 38 studies, mostly from high-income countries, many of which explored mothers' perceptions of vaccine communication. Some focused on the MMR (measles, mumps, rubella) vaccine.In general, parents wanted more information than they were getting (high confidence in the evidence). Lack of information led to worry and regret about vaccination decisions among some parents (moderate confidence).Parents wanted balanced information about vaccination benefits and harms (high confidence), presented clearly and simply (moderate confidence) and tailored to their situation (low confidence in the evidence). Parents wanted vaccination information to be available at a wider variety of locations, including outside health services (low confidence) and in good time before each vaccination appointment (moderate confidence).Parents viewed health workers as an important source of information and had specific expectations of their interactions with them (high confidence). Poor communication and negative relationships with health workers sometimes impacted on vaccination decisions (moderate confidence).Parents generally found it difficult to know which vaccination information source to trust and challenging to find information they felt was unbiased and balanced (high confidence).The amount of information parents wanted and the sources they felt could be trusted appeared to be linked to acceptance of vaccination, with parents who were more hesitant wanting more information (low to moderate confidence).Our synthesis and comparison of the qualitative evidence shows that most of the trial interventions addressed at least one or two key aspects of communication, including the provision of information prior to the vaccination appointment and tailoring information to parents' needs. None of the interventions appeared to respond to negative media stories or address parental perceptions of health worker motives. AUTHORS' CONCLUSIONS: We have high or moderate confidence in the evidence contributing to several review findings. Further research, especially in rural and low- to middle-income country settings, could strengthen evidence for the findings where we had low or very low confidence. Planners should consider the timing for making vaccination information available to parents, the settings where information is available, the provision of impartial and clear information tailored to parental needs, and parents' perceptions of health workers and the information provided.