Assertive communication skills are key to establishing and safe effective teamwork. Nursing education has long been recognized as important for providing the future workforce with high-calibre interpersonal skills, including assertive communication ones. Newly-graduated nurses are in a unique position to reflect on both their undergraduate nursing education and its contributions to their current communication practice. The aim of this research was to explore newly-graduated British and Saudi nurses’ views on the contributions of their undergraduate nursing education towards learning and practising assertive communication skills. A total of 96 newly-graduated British and Saudi nurses completed a survey with qualitative, open-ended questions between 2015 and 2017. The nurses reflected on learning and practising assertive communication skills during their undergraduate nursing education, and in their current clinical role. The nurses’ qualitative responses were analysed using thematic analysis. Three major themes were identified from data analysis: “Drivers for speaking up”, “The pedagogical context of speaking up” and “Ways of building self-confidence”. Undergraduate nursing education across both the UK and Saudi Arabia emphasizes the need to acquire the skills to communicate assertively in clinical settings. However, the nursing education received by the participants fails to address key operational skills which would help the nurses to translate such awareness into practice. Education and training must be matched by the elimination of implicit sanctions against speaking up in both educational and work settings. Future research needs to examine not only the operational skills that are necessary to challenge poor practice, but also the contributions of personality traits towards faster acquisition of assertiveness skills.