Introduction: Monitoring for adverse events following immunisation (AEFI) is critical for vaccine pharmacovigilance. Given the global and expanding availability of mobile phones their utility for consumer-based vaccine safety surveillance is of interest but little is known about consumer acceptability. This study nested within the Stimulated Telephone Assisted Rapid Safety Surveillance (STARSS) randomised control trial sought to evaluate the acceptability of SMS for AEFI surveillance. Methods: The primary STARSS study was a multi-centre RCT evaluating the efficacy of repeated SMS prompts for AEFI surveillance with participants being adult vaccinees or parents of children receiving any vaccine. This nested study enrolled primary RCT participants who completed a detailed computer assisted telephone interview to determine their attitudes towards SMS-based surveillance and ascertain their knowledge and attitudes toward vaccine safety, efficacy, data privacy and use of electronic health records. Attitudes to surveillance and related behaviour were used as measures of acceptability. Results: 20% (1200/6555) of the participants were enrolled and 1139 completed the full-length questionnaire. 96% indicated that SMS-based surveillance after immunisation to check the safety of the vaccine “should be done” but 62% of all respondents said it should be done but consent should be sought first. Neither vaccine safety attitudes nor attitudes toward privacy were associated with opposition to SMS-based surveillance. In terms of SMS related behaviour demographic rather than attitudinal factors were associated with non-compliance. Conclusion: Overall, the attitude towards SMS-based surveillance was very favourable. Experiencing the SMS surveillance has the effect of reducing opposition to an SMS surveillance system, and at the same time increasing the likelihood of a preference for prior consent. Detection of a vaccine safety signal could be impeded in particular demographic groups who are non-compliant and we should undertake further research to understand why these groups are non-compliant and how this can be improved.