To examine parental self-efficacy experiences for users of a parenting support programme and consider the pertinence of self-efficacy theory to health visiting (public health nursing) practice. Commonly, successful parenting training programmes are underpinned by social learning principles and aim to strengthen parental self-efficacy. However, research examining programme effectiveness rarely discusses how self-efficacy outcomes are achieved. A descriptive survey was completed as the first part of a realistic evaluation study examining how a UK parenting support programme worked. The first part of the realistic evaluation involved validating outcome measures (the Parenting Self-Agency Measure and Self-Efficacy for Parenting Tasks Index subscales) and administering a questionnaire survey. The questionnaire was completed by adults accessing a parenting support programme during a 10-month period (n = 168). Data were analysed using descriptive and inferential statistics. Women were the main users of the programme, which included informal drop-in groups as well as more formalised health visiting services and parenting training courses. The Parenting Self-Agency Measure results indicated good general parental self-efficacy; however, the task-specific Self-Efficacy for Parenting Tasks Indexes scales suggested that parents were less self-efficacious in disciplining children. Lower self-efficacy scores correlated with high ratings for 'feeling tired', 'receiving negative comments' and 'giving-in to a child's demands'. Study results indicate that the domain general and task-specific measures provide different, but helpful, insights into parental self-efficacy experiences. By identifying factors associated with the levels of general and task-specific parental self-efficacy, health visitors can gain a fuller appreciation of support needs. To maximise potential through parenting support, attention should be given to addressing factors associated with poorer self-efficacy experiences, including parental tiredness. Equally, practice should be directed at developing community environments that offer exposure to positive praise and the opportunity to practice new skills without facing criticism.