The purpose of this research was to ascertain how progressive muscle relaxation (PMR) technique affected hip fracture patients' anxiety, sleep quality, and post-operative pain. This parallel randomized controlled trial was conducted on 100 patients with hip fracture hospitalized in one of the reference orthopedic hospitals in Tehran, Iran who were selected using convenience sampling and randomly were placed in two PMR group (n = 50) and control group (n = 50). Data were collected by Demographic information questionnaire, Visual analogue scale for pain rating, Pittsburgh Sleep Quality Index and State-Trait Anxiety Inventory. The PMR technique was the progressive muscle relaxation technique, which was started the night after the surgery for three nights before going to bed. Data were collected on two occasions, including before the PMR technique and the day after the last stage of the PMR technique. The data were analyzed by SPSS software using descriptive and inferential statistics. The results revealed significant within-group changes in both groups' post-operative pain, sleep quality, and anxiety scores (P < 0.001). The progressive muscle relaxation group experienced decreased post-operative pain and anxiety scores and increased sleep quality scores (P < 0.001). The linear mixed model showed that the absolute changes in the follow-up post-operative pain, sleep quality, and anxiety scores were 1.19 and 7.94 units, significantly lower than the baseline, respectively. The results revealed significant within-group changes in both groups' post-operative pain, sleep quality, and anxiety scores (P < 0.001). The progressive muscle relaxation group experienced decreased post-operative pain and anxiety scores and increased sleep quality scores (P < 0.001). The study's findings demonstrated the beneficial effects of progressive muscle relaxation on hip fracture patients' outcomes, such as their level of anxiety, sleep quality, and post-operative pain. The study's findings can be applied by medical professionals to improve patient satisfaction and care quality.This clinical trial has been registered with the Iranian Registry of Clinical Trials under the code IRCT20231120060119N1, which was approved on 7/12/2023.