Background: Plastic is a major environmental hazard that poses potential threats to ecosystems and human health. Improper use and disposal of plastics contribute to pollution and health risks. Health education plays a crucial role in enhancing knowledge and promoting safe disposal practices. This study aimed to assess the effect of educational sessions about plastic usage hazards and safe disposal on the knowledge and reported practices of female employees at Port Said University. Methods: A quasi-experimental design was conducted among female employees at Port Said University, Egypt. A purposive sample of 130 women from six randomly selected faculties participated. Data was collected before and after the intervention using a structured questionnaire assessing knowledge of plastic hazards and reported disposal practices. Statistical analysis was performed using SPSS version 26, applying paired t-tests and chi-square tests to compare pre- and post-intervention results. The study followed the STROBE guidelines. Results: Before the intervention, only 33.1% of participants demonstrated adequate knowledge of the hazards associated with plastic use, which increased to 38.5% after the educational program. Regarding reported practices, 43.1% of participants exhibited moderate behavior prior to the intervention, which improved to 65.4% post-intervention. Statistical analysis revealed a significant improvement in overall knowledge and reported practice scores after the program (P < 0.05). Additionally, a significant positive correlation was found between knowledge and reported practices regarding plastic usage (P < 0.001), indicating that increased awareness was associated with safer disposal practices. Conclusions: Educational sessions significantly improved female employees’ knowledge and reported practices regarding plastic usage hazards and safe disposal. Workplace health education is an effective strategy for promoting environmental awareness and encouraging safer waste management behaviors. These findings support the integration of structured educational interventions in occupational health programs.