Two-sided assembly lines are often used at the assembly of large-sized high-volume products, such as cars, trucks, and buses. In this type of a production line, the left side and the right side of the line are used in parallel. This paper presents a tabu search algorithm for two-sided assembly line balancing. The line efficiency and the smoothness index are considered as the performance criteria. The proposed algorithm is illustrated with two numerical example problems, and its performance is tested on a set of test problems taken from literature. The performance of the proposed algorithm is compared to the existing approaches. The computational results show that the proposed algorithm performs well.