船形帽，又名侧边帽（英语：Side cap）是一种船型的军用帽。相较其他军用帽，船形帽具有易于携带储藏、不易遮挡视线的特点。

A side cap is a foldable military cap with straight sides and a creased or hollow crown sloping to the back where it is parted. It is known as a garrison cap or flight cap (in the United States), a wedge cap (in Canada), or officially field service cap (in the United Kingdom and Commonwealth countries), but it is more generally known as the side cap. It follows the style which originated with the so-called Austrian Cap in the 1890s. There was also a previous version known as the 'Torin', which had a much more curved top line when viewed from the side. Both Austrian and Torin types were distinguished by the inclusion of a fold-down section for warming the ears and back of the head in inclement weather. These two styles are still used by officers of some British units and continue to include this feature. In appearance the cap is similar to the Glengarry, but differs by a lack of the tartan, or check trim, toorie, and ribbons typical of the Scottish cap. It has been associated with various military forces from the time of World War I to the present day, and various youth organizations. A convenient feature of this cap is that when the owner is indoors and no coat-hook is available, it can be easily stored (by folding it over the belt or, unofficially, by tucking it under a shoulder strap).