  Orlicz-Lorentz spaces provide a common generalization of Orlicz spaces and
Lorentz spaces. In this paper, we investigate their Boyd indices. Bounds on the
Boyd indices in terms of the Matuszewska-Orlicz indices of the defining
functions are given. Also, we give an example to show that the Boyd indices and
Zippin indices of an Orlicz-Lorentz space need not be equal, answering a
question of Maligranda. Finally, we show how the Boyd indices are related to
whether an Orlicz-Lorentz space is p-convex or q-concave.
