  We analyze the production of neutral Higgs particles in association with the
supersymmetric scalar partners of the third generation quarks at future
high--energy hadron colliders [upgraded Tevatron, LHC] and $e^+e^-$ linear
machines [including the $\gamma \gamma$ option]. In the Minimal Supersymmetric
extension of the Standard Model, the cross section for the associated
production of the lightest neutral $h$ boson with the lightest top squark pairs
can be rather substantial at high energies. This process would open a window
for the measurement of the $h \tilde{t} \tilde{t}$ coupling, the potentially
largest coupling in the supersymmetric theory.
