Context: The obesity prevalence is rising in developed countries. Surgery is one of the available treatment methods. Among the surgical options, laparoscopic sleeve gastrectomy (LSG) is a common surgical intervention. Aim: To evaluate the effect of implementing nursing care standard on compliance and lifestyle behavior for patients' undergoing laparoscopic sleeve gastrectomy. Research design: A quasi-experimental (pre/post) design was employed in two settings (General surgery department and the surgical outpatient clinic) of University Hospital in Benha. Thirty nurses were conveniently recruited from both genders who provided direct care for LSG patients and a purposive sample of 72 patients from the same settings within a period of seven months were also recruited in this study. Tools: (I) a structured questionnaire for nurses that asked about personal information and knowledge of laparoscopic sleeve gastrectomy management; (II) an observational performance checklist for nurses' practice; and (III) interviewing questionnaire for patients' assessments. Results: The overall knowledge and practice scores of nurses showed a significant improvement following the implementation of nursing care standards. Additionally, patients demonstrated a statistically significant increase in compliance and adoption of health-promoting lifestyle behaviors three months after the standards were introduced, reflecting a substantial improvement. Furthermore, assessments conducted one month, and three months post-implementation revealed positive statistically significant correlations between nurses' knowledge and nurses' practices and the patients' compliance and health-promoting behaviors (P < 0.001). Conclusion: The application of nursing care standards had a statistically significant positive impact on the nurses' knowledge and practice scores of nurses who were exposed to laparoscopic sleeve gastrectomy standards of care, as evidenced by an increase in the mean scores for patient compliance and health lifestyle behavior. Recommendations: Delivering high-quality nursing care to patients undergoing laparoscopic sleeve gastrectomy requires a continuous and well-structured education and training program for nurses. Such a program should be offered regularly to enhance their knowledge and skills, ensuring alignment with the guidelines outlined in nursing care standards.