Nonlinear guidance laws considering impact time constraints are proposed. Two-dimensional and threedimensional impact time control guidance(ITCG) laws are derived using Lyapunov stability theory. Under the consideration of the nonlinear kinematics, it is shown that the missile states converge to the desired equilibrium point by the Lyapunov stability theory. The singularity issue of the proposed guidance laws is also analyzed. Numerical simulations are performed to verify the performance of the proposed guidance laws.