This study delves into the various factors that inhibit the growth of small and medium-sized enterprises (SMEs), with a specific emphasis on restaurants operating within Lusaka’s Central Business District (CBD). To achieve a comprehensive understanding of these challenges, the study adopted a mixed-methods research design, integrating both quantitative and qualitative data collection and analysis techniques. Quantitative data were collected through structured surveys administered to a randomly selected sample of 211 restaurant SMEs. This sizable sample ensures that the findings are statistically reliable and reflective of broader trends within the industry. In parallel, qualitative data were obtained through purposive sampling, guided by the saturation principal interviews continued until no new themes emerged. Data analysis was conducted using SPSS software for the quantitative component, allowing for the identification of patterns and correlations between variables. Thematic analysis was employed for the qualitative responses, enabling the extraction of recurring themes and deeper insights into the contextual and experiential dimensions of SME growth challenges. The findings of the study point to financial constraints as the most significant barrier to SME growth. Among the financial issues identified, lack of access to financing, high interest rates, and rigid collateral requirements stood out as major impediments. Notably, the quantitative analysis revealed a strong negative correlation between lack of financing and business growth, with a correlation coefficient of -0.927. This statistically significant result indicates that as access to financing decreases, the potential for business expansion and sustainability diminishes sharply. These findings align with existing literature on SME development in developing economies, where financial exclusion remains a pervasive issue. The consistency of the study’s results with global and regional trends underscores the systemic nature of these financial barriers.