We attempted to find out the most significant factors that affect the Business Success of SMEs in Thailand and
found out that SMEs characteristic, customer and market, the way of doing business and cooperation, resources
and finance, and external environment are the most significant determinants of Business Success of SMEs in
Thailand. Most of the Thailand SMEs adopted Porter’s Generic Strategies by Michael Porter; they are cost
leadership, differentiation, and focused. To ensure Thailand SMEs can continue successful they need to ensure
resources and finance and, customer and market are developed continuously. External Environment hypothesis
accepted as social network help entrepreneurs in Thailand to reduce risks and transaction costs, improve access
to business ideas, knowledge and capital. Government support in Thailand has help to foster SMEs development
and legal aspect is used in selection operating decision in order to ensure SMEs future business success. Hence,
Thailand SMEs should ensure they have built a strong social network and good government relationship in order
to ensure their business success. The Way of doing Business & Cooperation hypothesis accepted as inter-firm
cooperation contribute positively to gaining organizational legitimacy and to developing a desirable marketplace
reputation, and enable the small firm to improve its strategic position, focus on its core business, enter
international markets, reduce transaction costs, learn new skills, and cope positively with rapid technological
changes. Besides that, use of outside professionals and advisors should continue to be practiced by Thailand
SMEs