Medication errors have been the focus of considerable research attention in nursing; however, the extent to which nursing students might contribute to errors has not been researched. Using a grounded theory approach, in-depth semi-structured interviews were conducted with undergraduate nursing students based in a university in Queensland to explore their experiences of administering medication in the clinical setting. Almost a third of the participants reported making an actual medication error or a near miss. Where medication errors occurred, participants described not receiving direct and appropriate supervision by a registered nurse. Medication errors by nursing students have the potential to impact significantly on patient safety, quality of health care, and on nursing students’ perceptions of their professional competence. Ensuring direct supervision is provided at all times must become an urgent priority for undergraduate nursing education.