This study aimed to develop and test the validity and reliability of the Knowledge, Attitudes and Practices of Incontinence-associated Dermatitis Questionnaire (KAP-IAD-Q) for Nurses. A psychometric validation design was employed. Phase I of the study entailed the development of items through an extensive literature review and a double Delphi procedure with 11 experts specialised in wound, ostomy and continence to examine content validity of the KAP-IAD-Q. Phase II involved administering the KAP-IAD-Q to a convenience sample of 263 Registered Nurses from a public hospital in Singapore to evaluate its construct validity, internal consistency and test-retest reliability. The instrument showed acceptable content validity (S-CVI = 0.85). Exploratory factor analysis showed all 22 items demonstrated strong factor loadings >0.4 and the four factors KAP-IAD-Q explained 58.1% of total variance. The four factors were☹1) knowledge om IAD aetiology and identification, (2) knowledge on IAD risk factors; (3) attitudes, and (4) practices. The overall internal consistency was excellent (Cronbach's α = 0.913). The KAP-IAD-Q showed good overall test-retest reliability as well (ICC = 0.89 (95% CI 0.69-0.96, p < 0.001). The KAP-IAD-Q demonstrated good psychometric properties and is effective in measuring levels of IAD-related KAP among nurses. Further confirmation of the proposed factor structure is recommended. Future research should explore determinants of nurses' KAP and associations between IAD knowledge, attitudes and practices. Copyright © 2020 Tissue Viability Society. Published by Elsevier Ltd. All rights reserved.