Small and medium-sized enterprises (SMEs) serve as vital pillars of the Palestinian economy by creating job opportunities and driving innovation. However, their sustainable growth and performance are impeded by limited access to credit, especially external funding, which ultimately caused it to withdraw from the market and the competition. This study explores the potential of peer-to-peer (P2P) lending Fintech and business support services to bridge the financial gap and foster sustainable growth in Palestinian SMEs while highlighting the mediating role of financial access in these relationships. The deductive approach was used, focusing on quantitative research, primary data was collected using a non-probability sampling strategy known as convenience sampling, using a developed questionnaire, and statistical analysis was done using PLS-SEM. The study targeted a community of 4374 diverse Palestinian small and medium enterprises. Potential respondents include owners, CEOs, and CFOs. Therefore. The final valid number was a convenient sample of 363 small and medium-sized enterprises. The findings demonstrated a significant mediation effect of access to finance on the relationship between P2P lending, Business support services, and sustainable growth. Furthermore, the study recommended the necessity of adopting BSS and P2P systems by decision-makers in Palestine, where the study provided valuable insights into the impact of P2P lending Fintech lending and business support services on Palestinian SMEs’ financial access and sustainable growth.