This research aims to evaluate the influence of financial structure on firm performance. At the same time, it analyzes the moderating function of financial risk in the relationship between financial structure and firm performance listed on Vietnam’s stock market. The author carried out a quantitative analysis. The data was gathered from 505 firms listed on the stock market in Vietnam in ten years from 2012 to 2021. The study’s outcomes demonstrate that: (i) financial structure has a positive impact on firm performance; (ii) financial risk plays a crucial role in controlling the mutual impact between financial structure and business performance. In addition, the research results also confirm the impact of a growth opportunity and liquidity ability on business performance. This research’s results support the trade-off theory of financial structure.