The Vietnamese government has advocated developing an export-based economy. In fact, the Prime Minister issued Decision No. 2471/QD-TTg dated December 28, 2011, approving the strategy of import and export of goods for the period 2011 to 2020, with a vision to 2030 formulating policies on development of logistics services, credit, and investment to develop export production, and customs clearance places for import and export goods. That fact prompted us to conduct the research investigating the impact of export support policies on export performance of firms locating in Ho Chi Minh City. The combination of qualitative and quantitative research method was applied. The netnography method and in-depth interview were used to explore support policies influencing export performance, and found Tax Incentives, Credit Incentives, Trade Promotion Support, and Custom Procedures Reform are four policies significantly explaining firms’ export performance. To measure the impact of these policies on export performance, we surveyed 141 firms in HCMC. The quantitative study confirmed that four policies impact positively significantly on export performance. The best explanatory factor is Trade Promotion Support, the second is Customs Procedure Reforms, followed by Tax Incentives. Credit incentives have the lowest effect on export performance. The findings asserted the positive effectiveness of policies promoting export performance implementing in Vietnam, and provided empirical evidence to support institutional theory.