Aims (1) To examine registered nurses' knowledge and confidence in recognizing and managing to patients with sepsis and (2) identify nurse and workplace factors that influence their knowledge on sepsis. Design A multi‐site, cross‐sectional survey. Methods An online survey was developed and content validated. Data was collected from registered nurses working in the inpatient wards and emergency departments of three hospitals of a single healthcare cluster in Singapore during August 2021. Statistical analyses of closed‐ended responses and content analysis of open‐ended responses were undertaken. Results A total of 709 nurses completed the survey. Nurses possessed moderate levels of knowledge about sepsis (mean score = 10.56/15; SD = 2.01) and confidence in recognizing and responding to patients with sepsis (mean score = 18.46/25; SD = 2.79). However, only 369 (52.0%) could correctly define sepsis. Nurses' job grade, nursing education level and clinical work area were significant predictors of nurses' sepsis knowledge. Specifically, nurses with higher job grade, higher nursing education level or those working in acute care areas (i.e. emergency department, high dependency units or intensive care units) were more likely to obtain higher total sepsis knowledge scores. A weak positive correlation was observed between sepsis knowledge test scores and self‐confidence (r = .184). Open comments revealed that participants desired for more sepsis education and training opportunities and the implementation of sepsis screening tool and sepsis care protocol. Conclusion A stronger foundation in sepsis education and training programs and the implementation of sepsis screening tools and care bundles are needed to enhance nurses' knowledge and confidence in recognizing and managing patients with sepsis. Impact The findings of this study are beneficial to administrators, educators and researchers in designing interventions to support nurses in their role in recognizing and responding to sepsis.