  The concept of scale factor duality is considered within the context of the
spatially homogeneous, vacuum Brans-Dicke cosmologies. In the Bianchi class A,
it is found that duality symmetries exist for the types I, II, VI_0, VII_0, but
not for types VIII and IX. The Kantowski-Sachs and locally rotationally
symmetric Bianchi type III models also exhibit a scale factor duality, but no
such symmetries are found for the Bianchi type V. In this way anisotropy and
spatial curvature may have important effects on the nature of such dualities.
