Background: Rotavirus is the leading cause of hospitalized diarrhea in Indonesia. Rotavirus vaccine has not been included on the Indonesian National Immunization Program (NIP). There are some key issues must be considered before introducing a new vaccine into a NIP. Our study aimed to explore the knowledge and attitudes of rotavirus diarrhea and barriers to the acceptance of the vaccine. Methods: We conducted 26 in-depth interviews in two districts (rural and urban areas) of Yogyakarta Province, Indonesia. Participants included pregnant women in their third trimester and mothers of infants aged less than 14 weeks. We conducted a thematic analysis. Results: Participants did not perceive diarrhea as being a priority health problem. Very few had heard of rotavirus diarrhea or were aware of the availability of the vaccine. While participants would accept a vaccine their children against rotavirus, some key barriers impacted the use of the vaccine. As the rotavirus vaccine is not included in the Indonesian National Immunisation Program (NIP), parents perceived it as not essential. Parents were concerned regarding the safety and benefit of the vaccine due to the perceived newness of the vaccine. Other concerns were the vaccine was too costly and the halal issue. Participants expressed a need for more information on the vaccine's effectiveness and safety, with their primary health care providers (HCPs) nominated as playing an important role in vaccine acceptance. Conclusions: There was low awareness of rotavirus being a serious disease and the availability of the rotavirus vaccine in Indonesia. The vaccine is not on the Indonesian NIP, the newness, the safety and efficacy, the cost, and the halal status of vaccine were barriers to vaccine acceptance. Information and recommendation by HCPs play an essential role in vaccine acceptance