Suction bucket foundation is a promising alternative for offshore wind turbine foundations. The lateral bearing behavior and failure mechanism are significant topics for optimizing its design criteria. In this study, a group of centrifuge tests were performed to investigate the lateral bearing capacity of suction bucket foundation with three aspect ratios. Force-controlled lateral static and cyclic tests were performed at a centrifuge acceleration of 50g. Four soil conditions were considered in centrifuge tests with a combination of loose/dense and dry/saturated sand. The load-displacement and the stiffness-displacement relationships are presented in the paper, and it is concluded that the lateral bearing capacity can be reached when the normalized lateral displacement (displacement divided by the bucket diameter) reached 3% as the first method. Displacement rates are plotted against the lateral load to give the second method for defining the ultimate lateral capacity. In cyclic tests, the lateral displacement and stiffness are correlated to the cycle numbers in the first 5 cycles, but the change is less apparent in the rest. The results demonstrated the behavior of bucket foundation in service conditions. Finally, a simplified calculation method is used as the third method and checked with tests results.