The cross sections for the multiple production of the lightest neutral Higgs boson at high-energy e + e - colliders are presented in the framework of the Minimal Supersymmetric extension of the Standard Model (MSSM). We consider production through Higgs-strahlung, associated production of the scalar and the pseudoscalar bosons, and the fusion mechanisms for which we use the effective longitudinal vector-boson approximation. These cross sections allow one to determine trilinear Higgs couplings λ H h h and λ h h h , which are theoretically determined by the Higgs potential.