Iranian Journal of Nursing and Midwifery Research1735-906631420260809576582Department of Psychiatric Nursing, School of Nursing and Midwifery, Isfahan University of Medical Sciences, Isfahan, IranDepartment of Psychiatric Nursing, School of Nursing and Midwifery, Isfahan University of Medical Sciences, Isfahan, IranDepartment of Psychiatric Nursing, School of Nursing and Midwifery, Isfahan University of Medical Sciences, Isfahan, Iran2026080320260803<p><strong>Background: </strong>Mothers of children with autism spectrum disorder (ASD) would experience elevated levels of stress and psychological distress. This study examined the effect of an online Mindfulness‑Based Stress Reduction (MBSR) Program on sleep quality in mothers of children with ASD. <strong>Materials and Methods: </strong>This was a randomized single‑blinded controlled trial that was conducted in 2022 on 72 mothers of children with ASD from Fatemeh Zahra and Parnian Autism Centers in Isfahan City, Iran. Participants were recruited through a convenient sampling and randomly assigned to intervention (<em>n </em>= 36) and control (<em>n </em>= 36) groups. The intervention group underwent eight 90‑min MBSR sessions twice a week. Data were collected using a demographic information form and the Pittsburgh Sleep Quality Index (PSQI) at baseline, immediately after, and one month after the intervention. Data were analyzed using independent samples: <em>t</em>‑test, Chi‑square, and one‑way repeated‑measure. <strong>Results: </strong>The intervention group showed significantly improved sleep quality scores immediately after (<em>F </em>= 107.004, <em>P </em>&lt; 0.001) and one month after (<em>F </em>= 107.004, <em>P </em>&lt; 0.001) the intervention compared to the control group (lower PSQI score indicates better sleep quality). Repeated‑measure ANOVA indicated a significant change in sleep quality scores over time within the intervention group (<em>F </em>= 107.004, <em>P </em>&lt; 0.05), but no significant change was found in the control group (<em>F </em>= 1.292, <em>P </em>&gt; 0.05). <strong>Conclusions: </strong>The findings of this study demonstrate that MBSR effectively improves sleep in mothers of children with ASD. Given its cost‑effectiveness, MBSR should be integrated into healthcare protocols.</p><p> </p>http://ijnmr.mui.ac.ir/index.php/ijnmr/article/view/2410http://ijnmr.mui.ac.ir/index.php/ijnmr/article/download/2410/70707997