Materials and Methods: The sequential combination exploratory mixed methods design was used to develop the questionnaire format in two sections: quantitative and qualitative. The qualitative section, designed to probe the role of cultural beliefs on weaning, included two steps: a literature and related tools review and fieldwork (semi-structured interviews with mothers). Twenty-two studies were examined in the literature review. Fourteen mothers were selected and interviewed by purposive sampling. Interviews continued up to data saturation. The data analyses for both steps were conducted using the conventional content analysis and textual content analysis. The quantitative section was a methodology study accomplished in two parts. Questionnaire items were formed using the data and items pool obtained from the first part. Psychometric properties of the questionnaire were checked using face, content, and construct validity, and reliability was probed using Cronbach’s alpha reliability in the second part.

Results: Qualitative data analysis results were organized according to the foundational issues regarding the need for weaning, attitude toward weaning, awareness about weaning, society’s culture, health literacy, self-action, others’ experiences, professional helps, family members’ support, and outcomes. The items pool was formed using literature reviews and interviews. The questionnaire containing 49 items was developed after completion of the psychometric process. The Kaiser-Meyer-Olkin (KMO) Index of Sampling Adequacy and Bartlett’s test of spheri city showed good results. Five components from the exploratory content analysis— contexts, solutions, searching for help, maternal outcomes, and child-related outcomes—showed a 62.2% variance. Cronbach’s alpha was 0.88 and the inter class correlation coefficient was 0.89, based on responses to the items over two administrations of the questionnaire (p < 0.001). These results showed a high level of tool stability.

Conclusion: For this study, a questionnaire was developed for understanding the role of cultural beliefs on weaning. It can be used for educational, research, and treatment purposes as a tool with appropriate validity and reliability and short, easy, and grammatically simple items. The questionnaire is useful for examining mothers’ false beliefs about weaning and their educational needs, as false beliefs could cause destructive and health threatening behaviors.