Objective: To investigate the association of nomophobia and insomnia with academic performance in medical students. Subjects and methods: 216 students of the University of Split School of Medicine participated in the study, of which 156 were women, 57 were men and 3 were of unspecified gender. The questionnaire was conducted online and consisted of three parts. In the first part of the questionnaire, demographic and anthropometric characteristics were assessed. The second part examined nomophobia using the NMP-Q questionnaire, and the third part examined insomnia symptoms using the ISI questionnaire. Results: 214 students (99,1%) suffered from nomophobia. The majority of students had moderate nomophobia (55,6%), followed by mild nomophobia (31,3%) and severe nomophobia (13,1%). Insomnia was more common in students with moderate or severe nomophobia than in students without or with mild nomophobia (7.85±5.24 vs. 6.19±4.89, P=0.024). In addition, students with moderate or severe nomophobia had worse quality of life (1.07±1.02 vs. 0.74±0.89, P=0.017) and more pronounced difficulty falling asleep (0.86±0.98 vs. 0.49±0.74, P=0.002) than students without or with mild nomophobia. Insomnia symptoms were more pronounced with increasing severity of nomophobia (r=0.172, P=0.012). There was no significant association between nomophobia and academic performance. There was a negative correlation between the weighted grade average and the severity of insomnia, the weighted grade average was lower in students with severe insomnia (r=-0.172, P=0.032). Conclusion: This research confirmed the association between nomophobia and insomnia in medical students. The symptoms of insomnia were more pronounced with increasing nomophobia severity. In addition, medical students with insomnia had a lower weighted grade average.