The aim of this study was to determine the effectiveness of virtual reality on anxiety, pain, sleep quality, and posttraumatic stress disorder in critically ill patients within intensive care units.The data sources included PubMed, EMBASE, Web of Science, CENTRAL, PsycINFO, and CINAHL DATA databases.Two authors independently conducted the literature search and quality assessment process. The pooled results were calculated using the standardised mean difference (SMD) and its 95% confidence interval (CI) using the Review Manager software (Version 5.4).Ten randomised controlled trials published from 2020 to 2024 were included. Most of the studies were classified as having a low risk of bias or some concerns. The evidence certainty varied from low to moderate for the different outcomes. The pooled results indicated statistically significant effectiveness in anxiety (SMD: -0.46, 95% CI: -0.80 to -0.11, P = 0.01) and sleep quality (SMD: 0.66, 95% CI: 0.29-1.03, P < 0.001) postintervention. No statistically significant effects were found for pain (SMD: -0.11, 95% CI: -0.79-0.57, P = 0.75) or posttraumatic stress disorder (SMD: -0.29, 95 % CI: -0.59-0.02, P = 0.06).Virtual reality is practical for mitigating anxiety and enhancing sleep quality in critically ill patients within intensive care units; however, its effects on pain and posttraumatic stress disorder are nonsignificant. Virtual reality can broaden its utility and content within intensive care units by incorporating meditation, hypnosis, and cognitive behavioural strategies. Careful consideration should be given to the timing and frequency of virtual reality sessions for patients who are critically ill and unable to remain conscious.Virtual reality is a promising complementary therapy in intensive care units. It can reduce anxiety and improve sleep quality. Still, its effects on pain and posttraumatic stress disorder are not significant, and future research should focus on optimising devices, expanding content, and selecting appropriate intervention timing and frequency.Copyright © 2025 Australian College of Critical Care Nurses Ltd. Published by Elsevier Ltd. All rights reserved.