The COVID-19 pandemic and containment measures adopted globally have entailed extensive changes to university students’ customary life, and they exhibit stress-related responses not only to fear of contagion but also to limitations of personal and relational life. This has resulted in widespread psychological symptoms reported by students worldwide, mainly in terms of anxiety and depression. Responding to the need to achieve a greater understanding of the impact of the COVID-19 pandemic among university students, the present study has a two-fold objective: 1. Describing a brief, valid and reliable tool, namely the COVID-19 Student Stress Questionnaire (CSSQ), which measures specific sources of stress featuring the COVID-19 pandemic lockdown experiences among university students (Stress related to changes in Relationships and Academic Life; Stress related to Isolation; Stress related to Fear of Contagion); 2. Providing examples of research applications of the COVID-19 Student Stress Questionnaire to understand the impact of specific COVID-19-related sources of stress on students’ psychological and physical health conditions. Research is discussed with the aim of providing tailored evidence-based clinical interventions to prevent mental disease escalation and to promote psychological adjustment during and after this exceptional global crisis. Implications for the healthcare sector and for healthcare professionals are discussed.