Background: Medical students, often high-achieving and motivated, face unique challenges as they transition to clinical practice. This professional identity formation process requires adapting to patient contact, clinical reasoning, and high-stakes assessments such as OSCEs. Alongside these demands, students struggle with perfectionist expectations, heavy workloads, and patient responsibilities, leading to fears of failure, inadequacy, or professional unpreparedness. International research shows recurring concerns, including breaking bad news, managing patients, and feelings of exclusion among international students. However, existing studies are limited by their cross-sectional focus and site-specific scope, lacking longitudinal data or cross-country comparisons. Addressing this gap is crucial for understanding how concerns evolve over time and for shaping unified, high-quality medical education. This study aims to explore medical students’ fears across different countries. Methods: In this study, we assessed the answers of medical students to the question, “What are you not looking forward to in your future job as a doctor?” This question was part of four questions of a longitudinal international survey aiming at students at the beginning and again towards the end of their studies. We analyzed responses given by medical students at the start of their studies at Ludwig-Maximilians University in Germany (LMU), Utrecht University in the Netherlands (UU), Karolinska Institutet in Sweden (KI) and the University of Nicosia in Cyprus (UNIC). A combination of qualitative analysis and hierarchical cluster analysis was used to identify recurring concerns, assess their importance, and examine differences based on university, gender, and societal context. Results: A total of 2048 responses were collected between 2017 and 2021. The analysis identified two predominant categories: “stress” and “working conditions”. The category “failure” ranked third overall, though it did not appear among the top four response categories at LMU. Ranks 3 and 4 consisted of the categories “healthcare system”, “hierarchy”, “bad news” and “work-life balance”. The distribution of these categories varied between countries. Conclusions: Quantifying students’ concerns and their prevalence enables international comparisons and highlights critical factors to address through systemic reforms targeted interventions. These findings provide valuable insights for improving students’ preparedness for medical practice.