Business-to-government (B2G) electronic auction (e-auction) markets are increasingly being used to create opportunities for suppliers to expand their market as well as trading activities. However, little has been done to understand the behaviour of suppliers participating in these markets. In this paper, we propose a framework to explain suppliers’ intention to participate, and the level of participation in B2G e-auction markets, which will be tested in the Thai B2G e-auction markets. Low supplier participation has been a major problem in the Thai e-auction markets. We posit that suppliers’ participation depends on organisational motivation, environmental uncertainty, and their capabilities. The conceptual framework draws from the Motivation-Ability Framework, Transaction Cost Theory, Institutional Theory, and Resource-Based Theory. It proposes that four key constructs - efficiency motive, legitimacy motive, environmental uncertainty, and organisational capabilities influence suppliers’ intention to participate as well as their participation level in B2G e-auction markets.