Early childhood education (ECE) is vital for children's development, especially from birth to age five. Yet, there remains significant variation in teachers' qualifications across different settings and countries. While previous research suggests that teachers' qualifications may influence children's development outcomes in early childhood education and care (ECEC) settings, the evidence is mixed and lacks systematic synthesis. This review examined the relationship between teachers' qualifications and development outcomes of children aged 0-5 years through a systematic analysis of recent empirical studies. Following PRISMA guidelines, 12 studies published between 2016-2023 were identified and analyzed. The findings suggest that some studies found positive associations between higher teachers' qualifications and children's cognitive, social-emotional, and academic outcomes, while others showed no significant relationship. The inconsistencies stem from varying definitions of teachers' qualifications, different measurement approaches, and the potential influence of mediating factors such as teacher-child interactions. This review emphasises the need for standardised methods to assess teachers' qualifications and development outcomes, as well as further research on how teachers' qualifications impact child development. This review offers a clear framework for understanding the link between qualifications and outcomes, lists assessment tools for early childhood development, and challenges simplistic assumptions about linear relationships.