This paper compares the technical efficiency of small and medium-sized enterprises (SMEs) with that of large firms and studies the factors influencing technical efficiency for Taiwan's electronics industry. Unlike conventional studies, we use two alternative approaches to control for the influence of size effect. One is the two-stage switching regression to correct for endogenous size effect on technical efficiency and, the other is, a metafrontier production function for firms in different groups. The main results are as follows. First, the average technical efficiency for large firms is higher than that of SMEs, without considering the size effect, and lower when considering the endogenous choice on firm size. This study cannot, therefore, conclude that there is a negative size-technical efficiency relationship. It however, sheds light on the importance of size effect on the size-technical efficiency nexus. Second, the estimates on the determinants of technical efficiency show that being a subcontractor has a statistically significant positive influence on SMEs' technical efficiency, but the effect decreases with firm size.