Doubly special relativity provides an intriguing scenario for studying possible modifications of special relativity. To the leading order of quantum corrections, the scenario is characterized simply by several free parameters in boost generators, dispersion relation and momentum addition law. In this scenario, we work out finite-boost transformations in 3 þ 1 dimensions. Constraints on parameters are obtained from compatibility analysis, in agreement with other studies. Combining two successive noncollinear boosts, we also obtain the Wigner rotation angle in this scenario. Our analysis is restricted mainly to the case of the commutative addition law.