Background Various factors affect the use of physical restraints in the intensive care unit, with nurses’ knowledge and attitudes being the strongest determinants. Objective To determine Turkish intensive care unit nurses’ knowledge, attitudes, and practices regarding physical restraints and factors influencing them. Methods This cross-sectional, correlational study was conducted in the intensive care units of state and university hospitals. A total of 191 nurses provided information on their sociodemographic and professional characteristics and completed a questionnaire on their knowledge, attitudes, and practices regarding physical restraints. Results Statistically significant differences were found between average knowledge scores according to type of intensive care unit, weekly working hours, work shift, and frequency of using physical restraints, with the highest scores found in nurses who worked in the surgical unit, worked 40 hours a week, worked only during the day, and used physical restraints every day. Significant differences were found between average attitude scores according to type of intensive care unit, with the highest scores found in nurses who worked in the cardiology unit. Significant differences were found between average practice scores according to level of education and use of physical restraints without a physician’s order, with the highest scores found in nurses with undergraduate and postgraduate degrees and those who did not use physical restraints without a physician’s order. Conclusions This study revealed inadequate knowledge about physical restraints and some unsafe practices among participants. Evidence-based guidelines and laws regarding physical restraints are needed, as well as regular training programs for involved personnel.