The invention relates to a sports boot (1) for walking or cross-country skiing, with a flexible shaft (2) receiving the foot, and a reinforcement (5) surrounding the shaft (2) on its external side by sections and being connected with the outsole (3). The shaft (2) is formed in this connection by a cushioned inner boot (6), and a coat (8) of fabric o some other material compatible with the skin. The reinforcement (5) is formed by a latticed or net-like support structure (12) for the inner boot (6), and composed of flexible ribbon elements (13) having, however, the highest possible tensile strength, and being made of plastic or textiles, said ribbon elements resting against external part sections of the inner boot (6), or surrounding the inner boot (6) on its external side within part sections. In this connection, the latticed or net-like support structure (12) is variable with respect to its delimiting or receiving volume as required by means of a lacing system (14). In addition, a soft overstocking (16) is formed, which surrounds the latticed or net-like support structure (12) at least by sections, and serves there for sealing or shutting off the interior of the boot versus external environmental influences.