Background <p>Involving family members in delirium management with nurses’ guidance benefits both patients and families. However, studies of nurses’ beliefs and behavior about family engagement in preventing, detecting, and managing delirium remains limited.</p> Aims <p>To investigate the knowledge, attitudes, and practices (KAP) towards family engagement in delirium management among intensive care unit (ICU) nurses in China and the influencing factors.</p> Methods <p>A multicenter cross-sectional survey. From October to November 2024, ICU nurses from 17 hospitals in China participated in this study. Data was collected online using a self-developed questionnaire. This questionnaire aimed to evaluate ICU nurses’ KAP regarding family engagement in delirium management. Influencing factors were analyzed using Mann-Whitney U test and Kruskal-Wallis H test. Spearman correlation analysis and stratified regression analysis were conducted to assess the correlation among KAP.</p> Results <p>A total of 605 valid online questionnaires were collected, resulting in a 77.96% response rate. While ICU nurses exhibited high levels of knowledge and positive attitudes toward family engagement, with scoring rates of 80.20% and 82.85% respectively, their self-reported implementation in clinical practice remained insufficient at 72.57%. The univariate analysis showed that familiarity with the relevant guidelines and consensus, receipt of relevant training, and establishment of relevant departmental regulations were associated with ICU nurses’ KAP (<i>p</i> &lt; 0.05). Nurses with higher professional titles and more years of experience demonstrate more positive attitudes toward family engagement in delirium management (<i>p</i> &lt; 0.05). Those with greater work experience and higher educational levels tend to exhibit better practical practices (<i>p</i> &lt; 0.05). Both knowledge and attitude significantly influenced practice, with correlation coefficient of 0.561 and 0.469 respectively.</p> Conclusions <p>Our results contributed to the understanding of Chinese ICU nurses’ KAP about family engagement in delirium management. The results indicated that practice levels are low in comparison to knowledge and attitudes, and that knowledge and attitude were found to positively interact with practice. Therefore, the focus can be placed on improving nurses’ KAP regarding family engagement in delirium management, through targeted training programs and the development of standardized regulations by ICU administrators.</p> Clinical trial number <p>Not applicable.</p>