A sturdy portable massage roller that collapses flat. The roller includes an outer contact skin formed of a plurality of longitudinal stiffeners connected by longitudinally-extending hinge points, the contact skin defining an inner cavity. A collapsible support structure within the contact skin inner cavity is sized to contact and radially support the longitudinal stiffeners in the expanded shape of the contact skin, and is adapted to collapse so that the massage roller converts between a generally cylindrical expanded shape and a collapsed, flattened shape. The support structure may include a series of rigid discs that either pivot or are folded in half to convert the massage roller between its expanded and flat configurations.