Background and Purpose: Pre-service teachers’ professional identity is a dynamic and multidimensional construct that significantly influences their teaching attitudes, instructional practices, and educational quality. This systematic review aimed to analyze and compare national and international studies on the formation process of professional identity, influential factors, challenges, opportunities, and research gaps. Methods: Relevant studies were identified using Persian and English keywords in national and international databases. The selection process followed the PRISMA framework in four stages: identification, screening, eligibility, and inclusion. Inclusion criteria included a clear focus on pre-service teachers’ professional identity, publication within 2011–2025 (Persian studies) and 2010–2024 (international studies), and acceptable methodological quality. Out of 325 retrieved articles, 67 studies (15 national and 52 international) were selected for final analysis. Data analysis was conducted using a comparative-inductive content analysis approach, and quality assessment was performed using the CASP and MMAT tools. Findings: International studies emphasized individual factors such as emotion, self-efficacy, and agency, whereas national studies focused more on religious values and institutional structures. In both contexts, the significance of practicum experiences, social interactions, and cognitive-emotional dimensions of identity was highlighted. Qualitative approaches dominated the methodologies, with noticeable differences in research instruments. Common challenges included the gap between theory and practice, negative perceptions of the profession, and lack of conceptual coherence. Conclusion: The development of pre-service teachers’ professional identity requires an integration of practical experience, social support, and attention to both cognitive-emotional aspects and contextual specificities. Future research should address longitudinal designs, innovative interventions, and broader socio-political influences to