小型风帆战船（Sloop-of-war）是18世纪至19世纪，西方海军的一种战船，只有一层甲板，载有18门舰炮。按照英国皇家海军的分级系统，任何载有20门或20门以下舰炮的船只，都是小型风帆战船，所以，就连非常小的双桅横帆船和独桅纵帆船都是小型风帆战船。在技术上来讲，特种战船，如迫击炮船（Bomb vessel）和火船都是小型风帆战船，而且，实际上，他们不执行特殊任务的时候，的确担当了小型风帆战船的角色。进入20世纪之后，小型风帆战船演变为具有防空和反潜能力的近岸防御船只。

In the 18th and most of the 19th centuries, a sloop-of-war in the Royal Navy was a warship with a single gun deck that carried up to eighteen guns. The rating system covered all vessels with 20 guns and above; thus, the term sloop-of-war actually encompassed all the unrated combat vessels, including the very small gun-brigs and cutters. In technical terms, even the more specialised bomb vessels and fireships were classed as sloops-of-war, and in practice these were actually employed in the sloop role when not carrying out their specialized functions.