Introduction: Biomedical science courses, including anatomy, physiology, and biochemistry, are challenging for many undergraduate nursing students. This study explored academic achievement in these subjects and the impact of student educational factors on performance among nursing students in Uganda. Methods: Analytical cross-sectional study of 208 nursing students from four Ugandan public universities examined academic achievement in biomedical sciences. Using Grade Point Average (GPA) and letter grades as measures, the study analysed the influence of student educational factors like prior academic performance, career choice, and learning methods through Welch's Analysis of Variance, Pearsons's correlation and Linear Mixed-Effects model. Results: Academic achievement varied slightly across universities, with physiology having the highest mean GPA of 2.89 (1.83-3.70) and anatomy the lowest at 2.63 (2.04-3.30), resulting in an overall GPA of 2.80 ± 0.747. Most students received C (37%) and D (33.7%) grades. Choosing nursing as a lower-priority career ([beta] = 0.42, 95% CI 0.08-0.76, p = 0.02) and infrequent participation in group discussions ([beta] = -0.61, CI -1.21 to -0.12, p < 0.001) influenced academic achievement in biomedical sciences. Secondary school performance showed negligible correlation with biomedical science GPA (r = 0.1163). Conclusion: Academic achievement in biomedical sciences among Ugandan nursing students is marginal to moderate, with most earning C and D grades. Universities should provide extra support to students who select nursing as their first choice while continuing to admit those who choose nursing as a later option. Encouraging small group discussions among students could also be beneficial.