This paper investigate the degree to which environment uncertainty affects inter-organisational alliance partner selection in small to medium-sized enterprises and blends the resource-based view in a multiple-mediator model in which different dimensions of alliance motivation (cost and strategy) act as mediating mechanisms that transmit the positive effects of environment uncertainty to partner selection criteria. Four hypotheses are developed and then tested on a survey data sample of 108 firms in the Taiwanese steel industry. Our research findings show the mediating effects of alliance motivation cost and strategy and understanding how environment uncertainty impacts alliance motivation (cost and strategy) within small to medium-sized enterprises.