Assertiveness is a significant communication style for nursing students- as future professionals. Assertiveness is a vital skill for nursing students to communicate professionally and have been associated with high self- esteem. Aim: The aim of study is to assess the effect of assertiveness training program on university nursing students' self-esteem and communication skills. Research design: A quasi -experimental research design was used. Setting: The study was carried out at the psychiatric and mental health nursing classes, Faculty of Nursing - Helwan University. Sample: A convenience sample of (104) university nursing students were included for the conduction of this study. Tools of data collection: The study tools divided into four tools. I: Socio-demographic Sheet. II: Rathus Assertiveness Scale. III: Rosenberg Self Esteem Scale and IV: Communication Skills Scale. Results: There was significant changes in total score of assertiveness skills, self-esteem and communication skill levels of the studied nursing student at p≤ 0.05. In addition, there was a highly statistically significant difference between total mean scores of self- esteem, assertiveness skills, and communication skills among the studied sample post- program implementation compared to pre-program implementation. Conclusion: Assertiveness training program have a positive effect on communication skills and self-esteem of nursing students. Recommendation: Incorporating assertiveness training as an eligible training course of the undergraduate nursing program.