Background: Irritable bowel syndrome (IBS) is a common disorder with a significant impact on the patients’ quality of life. The objective if this study was to develop and validate knowledge, attitude, and practices (KAP) questionnaire in patients with IBS.Methods: The questionnaire was developed by medical experts by a consultative process using available literature on KAP for patients with IBS. Contents of the questionnaire were validated based on content clarity and relevance using a 4-point ordinal scale. A cross-sectional survey of 100 individuals with IBS was carried out to establish internal consistency, followed by the establishment of the construct validity of the questionnaire.Results: The original KAP questionnaire included 32 items categorized under the 3 domains of knowledge (22 items), attitude (6 items), and practices (8 items). During expert validation, 4 items from knowledge domain and 1 item from attitude domain were revised. For the original questionnaire, for the individual KAP domains and the overall questionnaire, the Cronbach's alpha raw values were 0.384, 0.215, 0.548, and ‑0.028, and standardized values were 0.395, 0.368, 0.490, and 0.119, respectively. Six items from knowledge domain and 1 item from attitude domain were deleted to strengthen the internal consistency without jeopardizing the purpose of study. For the questionnaire with 29 items, Cronbach's alpha values improved to 0.603, 0.314, 0.548, and 0.483 (raw values) and 0.586, 0.350, 0.490, and 0.414 (standardized values), respectively.Conclusions: The validated questionnaire with 29 items had improved homogeneity as compared with the initial questionnaire with 36 items.